ValueTracking: Handle canonicalize in CannotBeNegativeZero

Also fix apparently missing test coverage for any of the
handling here.

llvm-svn: 339023

2 files changed, 51 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index afaa800ede9..2aac19a49a5 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -2745,6 +2745,7 @@ bool llvm::CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI,
       break;
     // sqrt(-0.0) = -0.0, no other negative results are possible.
     case Intrinsic::sqrt:
+    case Intrinsic::canonicalize:
       return CannotBeNegativeZero(Call->getArgOperand(0), TLI, Depth + 1);
     // fabs(x) != -0.0
     case Intrinsic::fabs:
diff --git a/llvm/test/Transforms/InstSimplify/fast-math.ll b/llvm/test/Transforms/InstSimplify/fast-math.ll
index 67419048669..c129d19a4b1 100644
--- a/llvm/test/Transforms/InstSimplify/fast-math.ll
+++ b/llvm/test/Transforms/InstSimplify/fast-math.ll
@@ -226,6 +226,53 @@ define float @nofold_fadd_x_0(float %a) {
   ret float %no_zero
 }
 
+; CHECK-LABEL: @fold_fadd_nsz_x_0(
+; CHECK-NEXT: ret float %a
+define float @fold_fadd_nsz_x_0(float %a) {
+  %add = fadd nsz float %a, 0.0
+  ret float %add
+}
+
+; CHECK-LABEL: @fold_fadd_cannot_be_neg0_nsz_src_x_0
+; CHECK-NEXT: %nsz = fmul nsz float %a, %b
+; CHECK-NEXT: ret float %nsz
+define float @fold_fadd_cannot_be_neg0_nsz_src_x_0(float %a, float %b) {
+  %nsz = fmul nsz float %a, %b
+  %add = fadd float %nsz, 0.0
+  ret float %add
+}
+
+; CHECK-LABEL: @fold_fadd_cannot_be_neg0_fabs_src_x_0(
+; CHECK-NEXT: @llvm.fabs.f32
+; CHECK-NEXT: ret float %fabs
+define float @fold_fadd_cannot_be_neg0_fabs_src_x_0(float %a) {
+  %fabs = call float @llvm.fabs.f32(float %a)
+  %add = fadd float %fabs, 0.0
+  ret float %add
+}
+
+; CHECK-LABEL: @fold_fadd_cannot_be_neg0_sqrt_nsz_src_x_0(
+; CHECK-NEXT: fmul
+; CHECK-NEXT: call float @llvm.sqrt.f32
+; CHECK-NEXT: ret float %sqrt
+define float @fold_fadd_cannot_be_neg0_sqrt_nsz_src_x_0(float %a, float %b) {
+  %nsz = fmul nsz float %a, %b
+  %sqrt = call float @llvm.sqrt.f32(float %nsz)
+  %add = fadd float %sqrt, 0.0
+  ret float %add
+}
+
+; CHECK-LABEL: @fold_fadd_cannot_be_neg0_canonicalize_nsz_src_x_0(
+; CHECK-NEXT: fmul nsz
+; CHECK-NEXT: call float @llvm.canonicalize.f32(
+; CHECK-NEXT: ret float %canon
+define float @fold_fadd_cannot_be_neg0_canonicalize_nsz_src_x_0(float %a, float %b) {
+  %nsz = fmul nsz float %a, %b
+  %canon = call float @llvm.canonicalize.f32(float %nsz)
+  %add = fadd float %canon, 0.0
+  ret float %add
+}
+
 ; fdiv nsz nnan 0, X ==> 0
 ; 0 / X -> 0
 
@@ -396,3 +443,6 @@ define double @sqrt_squared_not_fast_enough3(double %f) {
   ret double %mul
 }
 
+declare float @llvm.fabs.f32(float)
+declare float @llvm.sqrt.f32(float)
+declare float @llvm.canonicalize.f32(float)