[llvm] f0cdf4b - [InstCombine] Check FPMathOperator for Ctx before FMF check

[Anna Thomas via llvm-commits]

Author: Anna Thomas
Date: 2023-11-07T10:50:19-05:00
New Revision: f0cdf4b468f6ee48b0d0d51ce78145455e2f07a6

URL: https://github.com/llvm/llvm-project/commit/f0cdf4b468f6ee48b0d0d51ce78145455e2f07a6
DIFF: https://github.com/llvm/llvm-project/commit/f0cdf4b468f6ee48b0d0d51ce78145455e2f07a6.diff

LOG: [InstCombine] Check FPMathOperator for Ctx before FMF check

We need to check FPMathOperator for Ctx instruction before checking fast
math flag on this Ctx.

Ctx is not always an FPMathOperator, so explicitly check for it.

Fixes #71548.

Added: 
    

Modified: 
    llvm/lib/Analysis/InstructionSimplify.cpp
    llvm/test/Transforms/InstCombine/minimum.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 5fa0a62c5c9adf1..ad51e163062012e 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -6606,7 +6606,8 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
     // float, if the ninf flag is set.
     const APFloat *C;
     if (match(Op1, m_APFloat(C)) &&
-        (C->isInfinity() || (Q.CxtI->hasNoInfs() && C->isLargest()))) {
+        (C->isInfinity() || (isa<FPMathOperator>(Q.CxtI) &&
+                             Q.CxtI->hasNoInfs() && C->isLargest()))) {
       // minnum(X, -inf) -> -inf
       // maxnum(X, +inf) -> +inf
       // minimum(X, -inf) -> -inf if nnan

diff  --git a/llvm/test/Transforms/InstCombine/minimum.ll b/llvm/test/Transforms/InstCombine/minimum.ll
index 71e6fec245c6b40..eb6eadf96e1323a 100644
--- a/llvm/test/Transforms/InstCombine/minimum.ll
+++ b/llvm/test/Transforms/InstCombine/minimum.ll
@@ -471,3 +471,29 @@ define double @negated_op_extra_use(double %x) {
   %r = call double @llvm.minimum.f64(double %negx, double %x)
   ret double %r
 }
+
+; Testcase from PR 71548.
+define void @pr71548() {
+; CHECK-LABEL: @pr71548(
+; CHECK-NEXT:    [[C0:%.*]] = load atomic double, ptr addrspace(1) null unordered, align 8
+; CHECK-NEXT:    [[C1:%.*]] = load atomic i32, ptr addrspace(1) null unordered, align 4
+; CHECK-NEXT:    [[C2:%.*]] = sitofp i32 [[C1]] to double
+; CHECK-NEXT:    [[CRES_I:%.*]] = call noundef double @llvm.minimum.f64(double [[C0]], double [[C2]])
+; CHECK-NEXT:    [[C3:%.*]] = fcmp ult double [[CRES_I]], 0.000000e+00
+; CHECK-NEXT:    [[C_NOT16:%.*]] = icmp eq i32 [[C1]], 0
+; CHECK-NEXT:    [[COR_COND45:%.*]] = or i1 [[C3]], [[C_NOT16]]
+; CHECK-NEXT:    call void @llvm.assume(i1 [[COR_COND45]])
+; CHECK-NEXT:    ret void
+;
+  %c0 = load atomic double, ptr addrspace(1) null unordered, align 8
+  %c1 = load atomic i32, ptr addrspace(1) null unordered, align 4
+  %c2 = sitofp i32 %c1 to double
+  %cres.i = call noundef double @llvm.minimum.f64(double %c0, double %c2)
+  %c3 = fcmp ult double %cres.i, 0.000000e+00
+  %c.not16 = icmp eq i32 %c1, 0
+  %cor.cond45 = or i1 %c3, %c.not16
+  call void @llvm.assume(i1 %cor.cond45)
+  ret void
+}
+
+declare void @llvm.assume(i1)