deps: V8: backport 3f071e3e7e15

Original commit message: PPC: Optimize clearing higher bits of mulhw/mulhwu Change-Id: Ie3e14a6ef4531349e81a8ae741bc7470c7e547ca Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2349468 Reviewed-by: Junliang Yan <[email protected]> Commit-Queue: Milad Farazmand <[email protected]> Cr-Commit-Position: refs/heads/master@{#69343} Refs: v8/v8@3f071e3 Backport-PR-URL: #35305 PR-URL: #35305 Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Ash Cripps <[email protected]>

Author: Milad Fa

common.gypi

@@ -34,7 +34,7 @@
 
 # Reset this number to 0 on major V8 upgrades.
 # Increment by one for each non-official patch applied to deps/v8.
-'v8_embedder_string': '-node.41',
+'v8_embedder_string': '-node.42',
 
 ##### V8 defaults for Node.js #####
 

deps/v8/src/compiler/backend/ppc/code-generator-ppc.cc

@@ -1480,12 +1480,14 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
  }
 break;
 casekPPC_MulHigh32:
- __ mulhw(i.OutputRegister(), i.InputRegister(0), i.InputRegister(1),
- i.OutputRCBit());
+ __ mulhw(r0, i.InputRegister(0), i.InputRegister(1), i.OutputRCBit());
+// High 32 bits are undefined and need to be cleared.
+ __ clrldi(i.OutputRegister(), r0, Operand(32));
 break;
 casekPPC_MulHighU32:
- __ mulhwu(i.OutputRegister(), i.InputRegister(0), i.InputRegister(1),
- i.OutputRCBit());
+ __ mulhwu(r0, i.InputRegister(0), i.InputRegister(1), i.OutputRCBit());
+// High 32 bits are undefined and need to be cleared.
+ __ clrldi(i.OutputRegister(), r0, Operand(32));
 break;
 casekPPC_MulDouble:
 ASSEMBLE_FLOAT_BINOP_RC(fmul, MiscField::decode(instr->opcode()));