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[clang][sema] forbid '+f' on output register #75208

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[clang][sema] forbid '+f' on output register #75208

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[clang][sema] forbid '+f' on output register
knightXun Dec 12, 2023
b2522c9
add ut
knightXun Dec 12, 2023
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9 changes: 8 additions & 1 deletion clang/lib/Basic/TargetInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
}
Comment on lines +720 to +728
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@phoebewang phoebewang Dec 13, 2023

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Need to change from here: https://github.com/llvm/llvm-project/blob/main/clang/lib/Basic/Targets/X86.cpp#L1436

Name++;
while (*Name) {
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14 changes: 14 additions & 0 deletions clang/test/Sema/asm.c
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Expand Up @@ -359,3 +359,17 @@ void test19(long long x)
// FIXME: This case should be supported by codegen, but it fails now.
asm ("" : "=rm" (x): "0" (e)); // expected-error {{unsupported inline asm: input with type 'st_size128' (aka 'struct _st_size128') matching output with type 'long long'}}
}

void test20()
{
double f00 = 0.0;
double f01 = 0.0;
double f10 = 0.0;
double f11 = 0.0;
int mem;
asm volatile ("" : "+f" (f00), "+f" (f01), "+f" (f10), "+f" (f11), "+m" (mem) :: "memory"); // expected-error {{invalid output constraint '+f' in asm}}
asm volatile ("" : "+r" (f00), "+f" (f01), "+f" (f10), "+f" (f11), "+m" (mem) :: "memory"); // expected-error {{invalid output constraint '+f' in asm}}
asm volatile ("" : "+r" (f00), "+r" (f01), "+f" (f10), "+f" (f11), "+m" (mem) :: "memory"); // expected-error {{invalid output constraint '+f' in asm}}
asm volatile ("" : "+r" (f00), "+r" (f01), "+r" (f10), "+f" (f11), "+m" (mem) :: "memory"); // expected-error {{invalid output constraint '+f' in asm}}
asm volatile ("" : "+r" (f00), "+r" (f01), "+r" (f10), "+r" (f11), "+m" (mem) :: "memory"); // no-error
}