{"commit":{"authoredAt":"2022-10-27T13:20:10-07:00","subject":"[ssa] Potential improvements to ssa construction","authorEmail":"josephsavona@users.noreply.github.com","revision":"fc1320552b0c36ce0bdbe985941398afcc43989a","shortRevision":"fc1320552b","authorName":"Joseph Savona"},"parents":["89151eb4871a040fea3e8cefd095019f63bc1876"],"body":"Redo of #711 \n\nNote that one test (switch.js) is failing, i'm working on a fix.","files":[{"status":"M","path":"compiler\/forget\/src\/HIR\/SSAify.ts"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/component.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-break.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-on-mutable.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/hooks-freeze-possibly-mutable-arguments.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/independent-across-if.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/interdependent-across-if.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/mutable-lifetime-loops.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/reassignment-conditional.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-complex-multiple-if.expect.md"},{"status":"A","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.expect.md"},{"status":"A","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.js"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch-non-final-default.expect.md"},{"status":"M","path":"compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch.expect.md"}],"patch":"diff --git a\/compiler\/forget\/src\/HIR\/SSAify.ts b\/compiler\/forget\/src\/HIR\/SSAify.ts\nindex 885ac5b0aa..7e43a6da19 100644\n--- a\/compiler\/forget\/src\/HIR\/SSAify.ts\n+++ b\/compiler\/forget\/src\/HIR\/SSAify.ts\n@@ -22,11 +22,10 @@ type State = {\n incompletePhis: IncompletePhi[];\n };\n \n-const unsealedPreds: Map = new Map();\n-\n class SSABuilder {\n #states: Map = new Map();\n #current: BasicBlock | null = null;\n+ unsealedPreds: Map = new Map();\n #env: Environment;\n \n constructor(env: Environment) {\n@@ -73,13 +72,13 @@ class SSABuilder {\n \n if (block.preds.size == 0) {\n \/\/ We're at the entry block and haven't found our defintion yet.\n- console.log(\n- `Unable to find \"${printIdentifier(oldId)}\", assuming it's a global`\n- );\n+ \/\/ console.log(\n+ \/\/ `Unable to find \"${printIdentifier(oldId)}\", assuming it's a global`\n+ \/\/ );\n return oldId;\n }\n \n- if (unsealedPreds.get(block)! > 0) {\n+ if (this.unsealedPreds.get(block)! > 0) {\n \/\/ We haven't visited all our predecessors, let's place an incomplete phi\n \/\/ for now.\n const newId = { ...oldId, id: this.nextIdentifierId };\n@@ -96,17 +95,45 @@ class SSABuilder {\n return newId;\n }\n \n- \/\/ There are multiple predecessors, we need a phi.\n- const newId = { ...oldId, id: this.nextIdentifierId };\n+ \/\/ There are multiple predecessors, we may need a phi.\n+ return this.maybeAddPhi(block, oldId, state);\n+ }\n+\n+ maybeAddPhi(block: BasicBlock, oldId: Identifier, state: State): Identifier {\n \/\/ Adding a phi may loop back to our block if there is a loop in the CFG. We\n \/\/ update our defs before adding the phi to terminate the recursion rather than\n \/\/ looping infinitely.\n+ const newId = { ...oldId, id: this.nextIdentifierId };\n state.defs.set(oldId, newId);\n- this.addPhi(block, oldId, newId);\n \n- \/\/ TODO(gsn): Can we just return `newPlace` rather than looking it up?\n- \/\/ `addPhi` _can_ mutate it, but _will_ it?\n- return state.defs.get(oldId)!;\n+ const predDefs: Map = new Map();\n+ const predIds: Set = new Set();\n+ for (const predBlock of block.preds) {\n+ const predId = this.getIdAt(oldId, predBlock);\n+ predDefs.set(predBlock, predId);\n+ predIds.add(predId);\n+ }\n+\n+ \/\/ if all predecessors have the same id, then there is no need for a phi node.\n+ \/\/ note that in the case of a loop there are guaranteed to be multiple values,\n+ \/\/ since we have already updated this block with a new identifier to terminate\n+ \/\/ the recursion\n+ if (predIds.size === 1) {\n+ \/\/ there was only a single incoming id so we don't need a phi node,\n+ \/\/ replace with that incoming id instead\n+ const predId = [...predIds][0]!;\n+ state.defs.set(oldId, predId);\n+ return predId;\n+ }\n+\n+ const phi: Phi = {\n+ kind: \"Phi\",\n+ id: newId,\n+ operands: predDefs,\n+ };\n+\n+ block.phis.add(phi);\n+ return newId;\n }\n \n addPhi(block: BasicBlock, oldId: Identifier, newId: Identifier) {\n@@ -197,14 +224,14 @@ export default function buildSSA(func: HIRFunction, env: Environment) {\n const outputBlocks = outputs.map((id) => func.body.blocks.get(id)!);\n for (const output of outputBlocks) {\n let count;\n- if (unsealedPreds.has(output)) {\n- count = unsealedPreds.get(output)! - 1;\n+ if (builder.unsealedPreds.has(output)) {\n+ count = builder.unsealedPreds.get(output)! - 1;\n } else {\n count = output.preds.size - 1;\n }\n- unsealedPreds.set(output, count);\n+ builder.unsealedPreds.set(output, count);\n \n- if (count == 0 && visitedBlocks.has(output)) {\n+ if (count === 0 && visitedBlocks.has(output)) {\n builder.fixIncompletePhis(output);\n }\n }\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/component.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/component.expect.md\nindex dacfe47037..8bc690d69c 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/component.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/component.expect.md\n@@ -44,11 +44,11 @@ bb0:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb4 bb7\n- items$33: phi(bb0: items$27, bb4: items$50, bb7: items$50)\n- item$35: phi(bb0: item$10, bb4: item$42, bb7: item$42)\n- seen$38: phi(bb0: seen$30, bb4: seen$41, bb7: seen$41)\n- renderedItems$46: phi(bb0: renderedItems$29, bb4: renderedItems$45, bb7: renderedItems$45)\n- max$48: phi(bb0: max$32, bb4: max$47, bb7: max$47)\n+ items$33: phi(bb0: items$27, bb4: items$33, bb7: items$33)\n+ item$35: phi(bb0: item$10, bb4: item$35, bb7: item$35)\n+ seen$38: phi(bb0: seen$30, bb4: seen$38, bb7: seen$38)\n+ renderedItems$46: phi(bb0: renderedItems$29, bb4: renderedItems$46, bb7: renderedItems$46)\n+ max$48: phi(bb0: max$32, bb4: max$48, bb7: max$48)\n If (read items$33) then:bb3 else:bb2\n bb3:\n predecessor blocks: bb1\n@@ -66,24 +66,18 @@ bb9:\n bb7:\n predecessor blocks: bb9 bb8\n $40: phi(bb9: $39, bb8: $37)\n- seen$41: phi(bb9: seen$38, bb8: seen$38)\n- item$42: phi(bb9: item$35, bb8: item$35)\n- renderedItems$45: phi(bb9: renderedItems$46, bb8: renderedItems$46)\n- max$47: phi(bb9: max$48, bb8: max$48)\n- items$50: phi(bb9: items$33, bb8: items$33)\n If (read $40) then:bb1 else:bb4\n bb4:\n predecessor blocks: bb7\n- Call mutate seen$41.add(mutate item$42)\n+ Call mutate seen$38.add(mutate item$35)\n Const mutate $43 = \"div\"\n- Const mutate $44 = JSX {read item$42}<\/read $43>\n- Call mutate renderedItems$45.push(read $44)\n- Const mutate $49 = Binary read renderedItems$45.length >= read max$47\n+ Const mutate $44 = JSX {read item$35}<\/read $43>\n+ Call mutate renderedItems$46.push(read $44)\n+ Const mutate $49 = Binary read renderedItems$46.length >= read max$48\n If (read $49) then:bb2 else:bb1\n bb2:\n predecessor blocks: bb1 bb4\n- renderedItems$51: phi(bb1: renderedItems$46, bb4: renderedItems$45)\n- Const mutate count$52 = read renderedItems$51.length\n+ Const mutate count$52 = read renderedItems$46.length\n Const mutate $53 = \"div\"\n Const mutate $54 = \"\\n \"\n Const mutate $55 = \"h1\"\n@@ -91,7 +85,7 @@ bb2:\n Const mutate $57 = JSX {freeze count$52}{read $56}<\/read $55>\n Const mutate $58 = \"\\n \"\n Const mutate $59 = \"\\n \"\n- Const mutate $60 = JSX {read $54}{read $57}{read $58}{freeze renderedItems$51}{read $59}<\/read $53>\n+ Const mutate $60 = JSX {read $54}{read $57}{read $58}{freeze renderedItems$46}{read $59}<\/read $53>\n Return read $60\n ```\n \ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-break.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-break.expect.md\nindex dad55cd5e6..b54e57a151 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-break.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-break.expect.md\n@@ -119,10 +119,8 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- a$5: phi(bb0: a$4, bb2: a$4)\n- props$6: phi(bb0: props$3, bb2: props$3)\n- Call mutate a$5.push(read props$6.d)\n- Return freeze a$5\n+ Call mutate a$4.push(read props$3.d)\n+ Return freeze a$4\n ```\n \n ## Code\n@@ -136,8 +134,8 @@ function Component$0(props$3) {\n (\"<>\");\n }\n \n- a$5.push(props$6.d);\n- return a$5;\n+ a$4.push(props$3.d);\n+ return a$4;\n }\n \n ```\n@@ -221,10 +219,8 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb2 bb0\n- a$5: phi(bb2: a$4, bb0: a$4)\n- props$6: phi(bb2: props$3, bb0: props$3)\n- Call mutate a$5.push(read props$6.d)\n- Return freeze a$5\n+ Call mutate a$4.push(read props$3.d)\n+ Return freeze a$4\n ```\n \n ## Code\n@@ -234,8 +230,8 @@ function Component$0(props$3) {\n const a$4 = [];\n a$4.push(props$3.a);\n if (props$3.b) {\n- a$5.push(props$6.d);\n- return a$5;\n+ a$4.push(props$3.d);\n+ return a$4;\n }\n \n a$4.push(props$3.c);\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-on-mutable.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-on-mutable.expect.md\nindex 00809fd0d8..a77b2aad7b 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-on-mutable.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/conditional-on-mutable.expect.md\n@@ -76,21 +76,14 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- props$9: phi(bb0: props$6, bb2: props$6)\n- b$10: phi(bb0: b$8, bb2: b$8)\n- Foo$12: phi(bb0: Foo$4, bb2: Foo$4)\n- a$14: phi(bb0: a$7, bb2: a$7)\n- If (read props$9.p1) then:bb4 else:bb3\n+ If (read props$6.p1) then:bb4 else:bb3\n bb4:\n predecessor blocks: bb1\n- Call mutate b$10.push(read props$9.p2)\n+ Call mutate b$8.push(read props$6.p2)\n Goto bb3\n bb3:\n predecessor blocks: bb1 bb4\n- Foo$11: phi(bb1: Foo$12, bb4: Foo$12)\n- a$13: phi(bb1: a$14, bb4: a$14)\n- b$15: phi(bb1: b$10, bb4: b$10)\n- Const mutate $16 = JSX <\/read Foo$11>\n+ Const mutate $16 = JSX <\/read Foo$4>\n Return read $16\n ```\n \n@@ -105,12 +98,12 @@ function Component$0(props$6) {\n (\"<>\");\n }\n \n- if (props$9.p1) {\n- b$10.push(props$9.p2);\n+ if (props$6.p1) {\n+ b$8.push(props$6.p2);\n (\"<>\");\n }\n \n- return <\/Foo$11>;\n+ return <\/Foo$4>;\n }\n \n ```\n@@ -128,21 +121,14 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- props$12: phi(bb0: props$8, bb2: props$8)\n- b$13: phi(bb0: b$10, bb2: b$10)\n- Foo$15: phi(bb0: Foo$6, bb2: Foo$6)\n- a$17: phi(bb0: a$9, bb2: a$9)\n- If (read props$12.p1) then:bb4 else:bb3\n+ If (read props$8.p1) then:bb4 else:bb3\n bb4:\n predecessor blocks: bb1\n- Call mutate b$13.push(read props$12.p2)\n+ Call mutate b$10.push(read props$8.p2)\n Goto bb3\n bb3:\n predecessor blocks: bb1 bb4\n- Foo$14: phi(bb1: Foo$15, bb4: Foo$15)\n- a$16: phi(bb1: a$17, bb4: a$17)\n- b$18: phi(bb1: b$13, bb4: b$13)\n- Const mutate $19 = JSX <\/read Foo$14>\n+ Const mutate $19 = JSX <\/read Foo$6>\n Return read $19\n ```\n \n@@ -157,12 +143,12 @@ function Component$0(props$8) {\n (\"<>\");\n }\n \n- if (props$12.p1) {\n- b$13.push(props$12.p2);\n+ if (props$8.p1) {\n+ b$10.push(props$8.p2);\n (\"<>\");\n }\n \n- return <\/Foo$14>;\n+ return <\/Foo$6>;\n }\n \n ```\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/hooks-freeze-possibly-mutable-arguments.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/hooks-freeze-possibly-mutable-arguments.expect.md\nindex 0394ddf0ed..ce9ad157e3 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/hooks-freeze-possibly-mutable-arguments.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/hooks-freeze-possibly-mutable-arguments.expect.md\n@@ -40,12 +40,10 @@ bb3:\n Goto bb1\n bb1:\n predecessor blocks: bb3 bb2\n- useFreeze$13: phi(bb3: useFreeze$5, bb2: useFreeze$5)\n a$14: phi(bb3: a$12, bb2: a$11)\n- call$15: phi(bb3: call$6, bb2: call$6)\n- Call read useFreeze$13(freeze a$14)\n- Call read useFreeze$13(read a$14)\n- Call mutate call$15(read a$14)\n+ Call read useFreeze$5(freeze a$14)\n+ Call read useFreeze$5(read a$14)\n+ Call mutate call$6(read a$14)\n Return read a$14\n ```\n \n@@ -64,9 +62,9 @@ function Component$0(props$7) {\n (\"<>\");\n }\n \n- useFreeze$13(a$14);\n- useFreeze$13(a$14);\n- call$15(a$14);\n+ useFreeze$5(a$14);\n+ useFreeze$5(a$14);\n+ call$6(a$14);\n return a$14;\n }\n \ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/independent-across-if.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/independent-across-if.expect.md\nindex 2537b2c99a..975bccc9ce 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/independent-across-if.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/independent-across-if.expect.md\n@@ -107,10 +107,7 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- Foo$11: phi(bb0: Foo$6, bb2: Foo$6)\n- a$12: phi(bb0: a$9, bb2: a$9)\n- b$13: phi(bb0: b$10, bb2: b$10)\n- Const mutate $14 = JSX <\/read Foo$11>\n+ Const mutate $14 = JSX <\/read Foo$6>\n Return read $14\n ```\n \n@@ -126,7 +123,7 @@ function Component$0(props$8) {\n (\"<>\");\n }\n \n- return <\/Foo$11>;\n+ return <\/Foo$6>;\n }\n \n ```\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/interdependent-across-if.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/interdependent-across-if.expect.md\nindex f0b150d952..331e700312 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/interdependent-across-if.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/interdependent-across-if.expect.md\n@@ -85,10 +85,7 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- Foo$11: phi(bb0: Foo$6, bb2: Foo$6)\n- a$12: phi(bb0: a$9, bb2: a$9)\n- b$13: phi(bb0: b$10, bb2: b$10)\n- Const mutate $14 = JSX <\/read Foo$11>\n+ Const mutate $14 = JSX <\/read Foo$6>\n Return read $14\n ```\n \n@@ -103,7 +100,7 @@ function Component$0(props$8) {\n (\"<>\");\n }\n \n- return <\/Foo$11>;\n+ return <\/Foo$6>;\n }\n \n ```\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/mutable-lifetime-loops.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/mutable-lifetime-loops.expect.md\nindex e75fc071f1..aee9e8df6c 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/mutable-lifetime-loops.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/mutable-lifetime-loops.expect.md\n@@ -104,7 +104,6 @@ bb2:\n b$31: phi(bb1: b$20, bb3: b$23)\n c$32: phi(bb1: c$22, bb3: c$25)\n d$33: phi(bb1: d$24, bb3: d$26)\n- mutate$35: phi(bb1: mutate$27, bb3: mutate$27)\n If (read a$30) then:bb7 else:bb7\n bb7:\n predecessor blocks: bb2\n@@ -118,7 +117,7 @@ bb11:\n bb13:\n predecessor blocks: bb11\n Const mutate $34 = null\n- Call mutate mutate$35(mutate d$33, read $34)\n+ Call mutate mutate$27(mutate d$33, read $34)\n Return\n ```\n \ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/reassignment-conditional.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/reassignment-conditional.expect.md\nindex e45c81ef9c..a9cef1b263 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/reassignment-conditional.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/reassignment-conditional.expect.md\n@@ -33,13 +33,10 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- Component$10: phi(bb0: Component$0, bb2: Component$0)\n x$11: phi(bb0: x$7, bb2: x$9)\n- y$13: phi(bb0: y$8, bb2: y$8)\n- props$14: phi(bb0: props$6, bb2: props$6)\n- Let mutate _$12 = JSX <\/read Component$10>\n- Call read y$13.push(read props$14.p2)\n- Const mutate $15 = JSX <\/read Component$10>\n+ Let mutate _$12 = JSX <\/read Component$0>\n+ Call read y$8.push(read props$6.p2)\n+ Const mutate $15 = JSX <\/read Component$0>\n Return read $15\n ```\n \n@@ -55,10 +52,10 @@ function Component$0(props$6) {\n (\"<>\");\n }\n \n- let _$12 = <\/Component$10>;\n+ let _$12 = <\/Component$0>;\n \n- y$13.push(props$14.p2);\n- return <\/Component$10>;\n+ y$8.push(props$6.p2);\n+ return <\/Component$0>;\n }\n \n ```\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-complex-multiple-if.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-complex-multiple-if.expect.md\nindex e2e54e6a7e..e4cb54c56a 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-complex-multiple-if.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-complex-multiple-if.expect.md\n@@ -32,10 +32,9 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb2\n- y$13: phi(bb0: y$8, bb2: y$8)\n x$17: phi(bb0: x$7, bb2: x$11)\n Const mutate $12 = 3\n- Const mutate $14 = Binary read y$13 === read $12\n+ Const mutate $14 = Binary read y$8 === read $12\n If (read $14) then:bb4 else:bb3\n bb4:\n predecessor blocks: bb1\n@@ -59,7 +58,7 @@ function foo$0() {\n (\"<>\");\n }\n \n- if (y$13 === 3) {\n+ if (y$8 === 3) {\n x$15 = 5;\n (\"<>\");\n }\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.expect.md\nnew file mode 100644\nindex 0000000000..70f5016359\n--- \/dev\/null\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.expect.md\n@@ -0,0 +1,51 @@\n+\n+## Input\n+\n+```javascript\n+function foo(cond) {\n+ let items = [];\n+ for (const item of items) {\n+ let y = 0;\n+ if (cond) {\n+ y = 1;\n+ }\n+ }\n+ return items;\n+}\n+\n+```\n+\n+## HIR\n+\n+```\n+bb0:\n+ Let mutate items$5 = Array []\n+ Goto bb1\n+bb1:\n+ predecessor blocks: bb0 bb3 bb5\n+ items$6: phi(bb0: items$5, bb3: items$6, bb5: items$6)\n+ cond$8: phi(bb0: cond$4, bb3: cond$8, bb5: cond$8)\n+ If (read items$6) then:bb3 else:bb2\n+bb3:\n+ predecessor blocks: bb1\n+ Let mutate y$7 = 0\n+ If (read cond$8) then:bb5 else:bb1\n+bb5:\n+ predecessor blocks: bb3\n+ Reassign mutate y$9 = 1\n+ Goto bb1\n+bb2:\n+ predecessor blocks: bb1\n+ Return freeze items$6\n+```\n+\n+## Code\n+\n+```javascript\n+function foo$0(cond$4) {\n+ let items$5 = [];\n+ (\"<>\");\n+}\n+\n+```\n+ \n\\ No newline at end of file\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.js b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.js\nnew file mode 100644\nindex 0000000000..3d040dd2a0\n--- \/dev\/null\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/ssa-for-of.js\n@@ -0,0 +1,10 @@\n+function foo(cond) {\n+ let items = [];\n+ for (const item of items) {\n+ let y = 0;\n+ if (cond) {\n+ y = 1;\n+ }\n+ }\n+ return items;\n+}\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch-non-final-default.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch-non-final-default.expect.md\nindex 009297f8a1..153648e33f 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch-non-final-default.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch-non-final-default.expect.md\n@@ -53,13 +53,10 @@ bb2:\n Goto bb1\n bb1:\n predecessor blocks: bb0 bb6 bb2\n- Component$17: phi(bb0: Component$0, bb6: Component$0, bb2: Component$0)\n- x$18: phi(bb0: x$10, bb6: x$10, bb2: x$10)\n y$20: phi(bb0: y$11, bb6: y$15, bb2: y$16)\n- props$21: phi(bb0: props$9, bb6: props$9, bb2: props$9)\n- Const mutate child$19 = JSX <\/read Component$17>\n- Call read y$20.push(read props$21.p4)\n- Const mutate $22 = JSX {read child$19}<\/read Component$17>\n+ Const mutate child$19 = JSX <\/read Component$0>\n+ Call read y$20.push(read props$9.p4)\n+ Const mutate $22 = JSX {read child$19}<\/read Component$0>\n Return read $22\n ```\n \n@@ -88,9 +85,9 @@ function Component$0(props$9) {\n }\n }\n \n- const child$19 = <\/Component$17>;\n- y$20.push(props$21.p4);\n- return {child$19}<\/Component$17>;\n+ const child$19 = <\/Component$0>;\n+ y$20.push(props$9.p4);\n+ return {child$19}<\/Component$0>;\n }\n \n ```\ndiff --git a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch.expect.md b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch.expect.md\nindex 921ed4febf..7fe21624d7 100644\n--- a\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch.expect.md\n+++ b\/compiler\/forget\/src\/__tests__\/fixtures\/hir\/switch.expect.md\n@@ -44,20 +44,14 @@ bb4:\n Goto bb2\n bb2:\n predecessor blocks: bb4 bb0\n- x$14: phi(bb4: x$9, bb0: x$9)\n- Component$17: phi(bb4: Component$0, bb0: Component$0)\n- props$22: phi(bb4: props$8, bb0: props$8)\n- Reassign mutate y$15 = read x$14\n+ Reassign mutate y$15 = read x$9\n Goto bb1\n bb1:\n predecessor blocks: bb2 bb0\n- Component$16: phi(bb2: Component$17, bb0: Component$0)\n- x$18: phi(bb2: x$14, bb0: x$9)\n y$20: phi(bb2: y$15, bb0: y$10)\n- props$21: phi(bb2: props$22, bb0: props$8)\n- Const mutate child$19 = JSX <\/read Component$16>\n- Call read y$20.push(read props$21.p4)\n- Const mutate $23 = JSX {read child$19}<\/read Component$16>\n+ Const mutate child$19 = JSX <\/read Component$0>\n+ Call read y$20.push(read props$8.p4)\n+ Const mutate $23 = JSX {read child$19}<\/read Component$0>\n Return read $23\n ```\n \n@@ -76,14 +70,14 @@ function Component$0(props$8) {\n }\n \n case false: {\n- y$15 = x$14;\n+ y$15 = x$9;\n (\"<>\");\n }\n }\n \n- const child$19 = <\/Component$16>;\n- y$20.push(props$21.p4);\n- return {child$19}<\/Component$16>;\n+ const child$19 = <\/Component$0>;\n+ y$20.push(props$8.p4);\n+ return {child$19}<\/Component$0>;\n }\n \n ```\n"}

dillon1000/react

Files changed