chore: cherry-pick ec6c18478382 from v8 (#48337)

* chore: cherry-pick ec6c18478382 from v8

* chore: update patches

* chore: update patches post-rebase
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Keeley Hammond 2025-09-16 23:24:49 -07:00 committed by GitHub
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chore_allow_customizing_microtask_policy_per_context.patch
cherry-pick-ec6c18478382.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Darius Mercadier <dmercadier@chromium.org>
Date: Tue, 16 Sep 2025 16:40:24 +0200
Subject: Don't assume that upper 32-bit of Int32MulOvfCheck are 0
Because Arm64 doesn't have a flag-setting 32-bit multiplication,
which means that instead with use a 64-bit multiplication, and compare
result.X() and result.W() to check if an overflow happened. But this
leads to the upper 32-bit not being zeroed.
Fixed: 445380761
Change-Id: I31287faf37dc615695047021324e9d1d802cbec2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6954290
Auto-Submit: Darius Mercadier <dmercadier@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#102530}
diff --git a/src/compiler/backend/arm64/instruction-selector-arm64.cc b/src/compiler/backend/arm64/instruction-selector-arm64.cc
index 60ff1ee97931edfcca28b6f5f7c4918d015af974..0212f4570750599bc266a1cd8c9efa19ea26e85c 100644
--- a/src/compiler/backend/arm64/instruction-selector-arm64.cc
+++ b/src/compiler/backend/arm64/instruction-selector-arm64.cc
@@ -2958,9 +2958,19 @@ bool InstructionSelector::ZeroExtendsWord32ToWord64NoPhis(OpIndex node) {
return op.Cast<ShiftOp>().rep == WordRepresentation::Word32();
case Opcode::kComparison:
return op.Cast<ComparisonOp>().rep == RegisterRepresentation::Word32();
- case Opcode::kOverflowCheckedBinop:
- return op.Cast<OverflowCheckedBinopOp>().rep ==
- WordRepresentation::Word32();
+ case Opcode::kOverflowCheckedBinop: {
+ const OverflowCheckedBinopOp& binop = op.Cast<OverflowCheckedBinopOp>();
+ if (binop.rep != WordRepresentation::Word32()) return false;
+ switch (binop.kind) {
+ case OverflowCheckedBinopOp::Kind::kSignedAdd:
+ case OverflowCheckedBinopOp::Kind::kSignedSub:
+ return true;
+ case OverflowCheckedBinopOp::Kind::kSignedMul:
+ // EmitInt32MulWithOverflow doesn't zero-extend because Arm64 doesn't
+ // have a flag-setting int32 multiplication.
+ return false;
+ }
+ }
case Opcode::kProjection:
return ZeroExtendsWord32ToWord64NoPhis(op.Cast<ProjectionOp>().input());
case Opcode::kLoad: {