[clang][sema] forbid '+f' on output register #75208
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to align with GCC asm: "+f" is not allowed to be used on output register. fix issue: llvm#75019
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| @llvm/pr-subscribers-clang Author: flyingcat (knightXun) Changesto align with GCC asm: "+f" is not allowed to be used on output register. fix issue: #75019 Full diff: https://github.com/llvm/llvm-project/pull/75208.diff 1 Files Affected:
diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp index 6cd5d618a4aca..57a81e03bc484 100644 --- a/clang/lib/Basic/TargetInfo.cpp +++ b/clang/lib/Basic/TargetInfo.cpp @@ -717,8 +717,15 @@ bool TargetInfo::validateOutputConstraint(ConstraintInfo &Info) const { if (*Name != '=' && *Name != '+') return false; - if (*Name == '+') + if (*Name == '+') { Info.setIsReadWrite(); + // To align with GCC asm: "=f" is not allowed, the + // operand constraints must select a class with a single reg. + auto Flag = Name + 1; + if (Flag && *Flag == 'f') { + return false; + } + } Name++; while (*Name) { |
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phoebewang reviewed Dec 13, 2023
Comment on lines +720 to +728
| if (*Name == '+') { | ||
| Info.setIsReadWrite(); | ||
| // To align with GCC asm: "=f" is not allowed, the | ||
| // operand constraints must select a class with a single reg. | ||
| auto Flag = Name + 1; | ||
| if (Flag && *Flag == 'f') { | ||
| return false; | ||
| } | ||
| } |
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Need to change from here: https://github.com/llvm/llvm-project/blob/main/clang/lib/Basic/Targets/X86.cpp#L1436
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to align with GCC asm: "+f" is not allowed to be used on output register.
fix issue: #75019