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[clang][x86] Ensure we use the shifted value bit width to check for out of bounds per-element shift amounts #156019

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Merged
RKSimon merged 1 commit into from
Aug 29, 2025
Merged

[clang][x86] Ensure we use the shifted value bit width to check for out of bounds per-element shift amounts #156019

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12 changes: 6 additions & 6 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3256,8 +3256,8 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
case clang::X86::BI__builtin_ia32_psllv8si:
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@RKSimon RKSimon Aug 29, 2025

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@Arghnews with this change you should be able to add the slli cases and reuse this code (same for the srli/srai cases as well below):

  case clang::X86::BI__builtin_ia32_psllwi128:
  case clang::X86::BI__builtin_ia32_psllwi256:
  case clang::X86::BI__builtin_ia32_psllwi512:
  case clang::X86::BI__builtin_ia32_pslldi128:
  case clang::X86::BI__builtin_ia32_pslldi256:
  case clang::X86::BI__builtin_ia32_pslldi512:
  case clang::X86::BI__builtin_ia32_psllqi128:
  case clang::X86::BI__builtin_ia32_psllqi256:
  case clang::X86::BI__builtin_ia32_psllqi512:

return interp__builtin_elementwise_int_binop(
S, OpPC, Call, BuiltinID, [](const APSInt &LHS, const APSInt &RHS) {
if (RHS.uge(RHS.getBitWidth())) {
return APInt::getZero(RHS.getBitWidth());
if (RHS.uge(LHS.getBitWidth())) {
return APInt::getZero(LHS.getBitWidth());
}
return LHS.shl(RHS.getZExtValue());
});
Expand All @@ -3266,8 +3266,8 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
case clang::X86::BI__builtin_ia32_psrav8si:
return interp__builtin_elementwise_int_binop(
S, OpPC, Call, BuiltinID, [](const APSInt &LHS, const APSInt &RHS) {
if (RHS.uge(RHS.getBitWidth())) {
return LHS.ashr(RHS.getBitWidth() - 1);
if (RHS.uge(LHS.getBitWidth())) {
return LHS.ashr(LHS.getBitWidth() - 1);
}
return LHS.ashr(RHS.getZExtValue());
});
Expand All @@ -3278,8 +3278,8 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
case clang::X86::BI__builtin_ia32_psrlv8si:
return interp__builtin_elementwise_int_binop(
S, OpPC, Call, BuiltinID, [](const APSInt &LHS, const APSInt &RHS) {
if (RHS.uge(RHS.getBitWidth())) {
return APInt::getZero(RHS.getBitWidth());
if (RHS.uge(LHS.getBitWidth())) {
return APInt::getZero(LHS.getBitWidth());
}
return LHS.lshr(RHS.getZExtValue());
});
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