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[clang] Fix invalid CodeGen for atomic fetch min/max on floating point values #162011

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[clang] Fix invalid CodeGen for atomic fetch min/max on floating point values #162011

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23 changes: 13 additions & 10 deletions clang/lib/CodeGen/CGAtomic.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -503,24 +503,27 @@ static void emitAtomicCmpXchgFailureSet(CodeGenFunction &CGF, AtomicExpr *E,
/// Duplicate the atomic min/max operation in conventional IR for the builtin
/// variants that return the new rather than the original value.
static llvm::Value *EmitPostAtomicMinMax(CGBuilderTy &Builder,
AtomicExpr::AtomicOp Op,
bool IsSigned,
llvm::Value *OldVal,
AtomicExpr::AtomicOp Op, bool IsInt,
bool IsSigned, llvm::Value *OldVal,
llvm::Value *RHS) {
llvm::CmpInst::Predicate Pred;
llvm::CmpInst::Predicate ICmpPred;
llvm::FCmpInst::Predicate FCmpPred;
switch (Op) {
default:
llvm_unreachable("Unexpected min/max operation");
case AtomicExpr::AO__atomic_max_fetch:
case AtomicExpr::AO__scoped_atomic_max_fetch:
Pred = IsSigned ? llvm::CmpInst::ICMP_SGT : llvm::CmpInst::ICMP_UGT;
ICmpPred = IsSigned ? llvm::CmpInst::ICMP_SGT : llvm::CmpInst::ICMP_UGT;
FCmpPred = llvm::FCmpInst::FCMP_UGT;
break;
case AtomicExpr::AO__atomic_min_fetch:
case AtomicExpr::AO__scoped_atomic_min_fetch:
Pred = IsSigned ? llvm::CmpInst::ICMP_SLT : llvm::CmpInst::ICMP_ULT;
ICmpPred = IsSigned ? llvm::CmpInst::ICMP_SLT : llvm::CmpInst::ICMP_ULT;
FCmpPred = llvm::FCmpInst::FCMP_ULT;
break;
}
llvm::Value *Cmp = Builder.CreateICmp(Pred, OldVal, RHS, "tst");
llvm::Value *Cmp = IsInt ? Builder.CreateICmp(ICmpPred, OldVal, RHS, "tst")
: Builder.CreateFCmp(FCmpPred, OldVal, RHS, "tst");
return Builder.CreateSelect(Cmp, OldVal, RHS, "newval");
}

Expand Down Expand Up @@ -760,9 +763,9 @@ static void EmitAtomicOp(CodeGenFunction &CGF, AtomicExpr *E, Address Dest,
// determine the value which was written.
llvm::Value *Result = RMWI;
if (PostOpMinMax)
Result = EmitPostAtomicMinMax(CGF.Builder, E->getOp(),
E->getValueType()->isSignedIntegerType(),
RMWI, LoadVal1);
Result = EmitPostAtomicMinMax(
CGF.Builder, E->getOp(), E->getValueType()->isIntegerType(),
E->getValueType()->isSignedIntegerType(), RMWI, LoadVal1);
else if (PostOp)
Result = CGF.Builder.CreateBinOp((llvm::Instruction::BinaryOps)PostOp, RMWI,
LoadVal1);
Expand Down
17 changes: 17 additions & 0 deletions clang/test/CodeGen/Atomics.c
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Expand Up @@ -12,6 +12,7 @@ signed long long sll;
unsigned long long ull;
__int128 s128;
unsigned __int128 u128;
float f;

void test_op_ignore (void) // CHECK-LABEL: define{{.*}} void @test_op_ignore
{
Expand Down Expand Up @@ -318,3 +319,19 @@ void test_atomic(void) {
ui = __atomic_fetch_max(&ui, 5, __ATOMIC_ACQUIRE); // CHECK: atomicrmw umax {{.*}} acquire, align 4
si = __atomic_fetch_max(&si, 5, __ATOMIC_RELEASE); // CHECK: atomicrmw max {{.*}} release, align 4
}

void test_atomic_minmax_fp(void) {
f = __atomic_fetch_min(&f, 5.0f, __ATOMIC_RELAXED);
// CHECK: atomicrmw fmin {{.*}} monotonic, align 4

f = __atomic_fetch_max(&f, 5.0, __ATOMIC_RELAXED);
// CHECK: atomicrmw fmax {{.*}} monotonic, align 4

f = __atomic_min_fetch(&f, 5.0, __ATOMIC_RELAXED);
// CHECK: atomicrmw fmin {{.*}} monotonic, align 4
// CHECK-NEXT: fcmp ult float {{.*}}, {{.*}}

f = __atomic_max_fetch(&f, 5.0, __ATOMIC_RELAXED);
// CHECK: atomicrmw fmax {{.*}} monotonic, align 4
// CHECK-NEXT: fcmp ugt float {{.*}}, {{.*}}
}