Index: lib/Analysis/ValueTracking.cpp =================================================================== --- lib/Analysis/ValueTracking.cpp +++ lib/Analysis/ValueTracking.cpp @@ -2037,6 +2037,7 @@ case Intrinsic::sqrt: case Intrinsic::fma: case Intrinsic::fmuladd: + case Intrinsic::fabs: return true; // TODO: some fp intrinsics are marked as having the same error handling // as libm. They're safe to speculate when they won't error. Index: test/Transforms/SimplifyCFG/speculate-math.ll =================================================================== --- test/Transforms/SimplifyCFG/speculate-math.ll +++ test/Transforms/SimplifyCFG/speculate-math.ll @@ -3,6 +3,7 @@ declare float @llvm.sqrt.f32(float) nounwind readonly declare float @llvm.fma.f32(float, float, float) nounwind readonly declare float @llvm.fmuladd.f32(float, float, float) nounwind readonly +declare float @llvm.fabs.f32(float) nounwind readonly ; CHECK-LABEL: @sqrt_test( ; CHECK: select @@ -21,6 +22,22 @@ ret void } +; CHECK-LABEL: @fabs_test( +; CHECK: select +define void @fabs_test(float addrspace(1)* noalias nocapture %out, float %a) nounwind { +entry: + %cmp.i = fcmp olt float %a, 0.000000e+00 + br i1 %cmp.i, label %test_fabs.exit, label %cond.else.i + +cond.else.i: ; preds = %entry + %0 = tail call float @llvm.fabs.f32(float %a) nounwind readnone + br label %test_fabs.exit + +test_fabs.exit: ; preds = %cond.else.i, %entry + %cond.i = phi float [ %0, %cond.else.i ], [ 0x7FF8000000000000, %entry ] + store float %cond.i, float addrspace(1)* %out, align 4 + ret void +} ; CHECK-LABEL: @fma_test( ; CHECK: select