[llvm] 0eddeea - [ValueTracking] Improve isKnownNonNaN() to recognize zero splats.

[Jonas Paulsson via llvm-commits]

Author: Jonas Paulsson
Date: 2020-02-19T09:35:36-08:00
New Revision: 0eddeeab29a1cce8f9169b270c9fdd484534d91b

URL: https://github.com/llvm/llvm-project/commit/0eddeeab29a1cce8f9169b270c9fdd484534d91b
DIFF: https://github.com/llvm/llvm-project/commit/0eddeeab29a1cce8f9169b270c9fdd484534d91b.diff

LOG: [ValueTracking]  Improve isKnownNonNaN() to recognize zero splats.

isKnownNonNaN() could not recognize a zero splat because that is a
ConstantAggregateZero which is-a ConstantData but not a ConstantDataVector.

Patch makes a ConstantAggregateZero return true.

Review: Thomas Lively

Differential Revision: https://reviews.llvm.org/D74263

Added: 
    llvm/test/CodeGen/SystemZ/vec-max-min-zerosplat.ll

Modified: 
    llvm/lib/Analysis/ValueTracking.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 3a76a6991715..0520ce5abc05 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4787,6 +4787,9 @@ static bool isKnownNonNaN(const Value *V, FastMathFlags FMF) {
     return true;
   }
 
+  if (isa<ConstantAggregateZero>(V))
+    return true;
+
   return false;
 }
 

diff  --git a/llvm/test/CodeGen/SystemZ/vec-max-min-zerosplat.ll b/llvm/test/CodeGen/SystemZ/vec-max-min-zerosplat.ll
new file mode 100644
index 000000000000..b4873edf9cea
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/vec-max-min-zerosplat.ll
@@ -0,0 +1,83 @@
+; Test vector maximum/minimum with a zero splat on z14.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z14 | FileCheck %s
+
+define <2 x double> @f1(<2 x double> %val) {
+; CHECK-LABEL: f1:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfmaxdb %v24, %v24, %v0, 4
+; CHECK-NEXT: br %r14
+  %cmp = fcmp ogt <2 x double> %val,  zeroinitializer
+  %ret = select <2 x i1> %cmp, <2 x double> %val, <2 x double> zeroinitializer
+  ret <2 x double> %ret
+}
+
+define <2 x double> @f2(<2 x double> %val) {
+; CHECK-LABEL: f2:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfmindb %v24, %v24, %v0, 4
+; CHECK-NEXT: br %r14
+  %cmp = fcmp olt <2 x double> %val,  zeroinitializer
+  %ret = select <2 x i1> %cmp, <2 x double> %val, <2 x double> zeroinitializer
+  ret <2 x double> %ret
+}
+
+define <4 x float> @f3(<4 x float> %val) {
+; CHECK-LABEL: f3:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfmaxsb %v24, %v24, %v0, 4
+; CHECK-NEXT: br %r14
+  %cmp = fcmp ogt <4 x float> %val,  zeroinitializer
+  %ret = select <4 x i1> %cmp, <4 x float> %val, <4 x float> zeroinitializer
+  ret <4 x float> %ret
+}
+
+define <4 x float> @f4(<4 x float> %val) {
+; CHECK-LABEL: f4:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfminsb %v24, %v24, %v0, 4
+; CHECK-NEXT: br %r14
+  %cmp = fcmp olt <4 x float> %val,  zeroinitializer
+  %ret = select <4 x i1> %cmp, <4 x float> %val, <4 x float> zeroinitializer
+  ret <4 x float> %ret
+}
+
+define <2 x double> @f5(<2 x double> %val) {
+; CHECK-LABEL: f5:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfmaxdb %v24, %v24, %v0, 1
+; CHECK-NEXT: br %r14
+  %cmp = fcmp ugt <2 x double> %val,  zeroinitializer
+  %ret = select <2 x i1> %cmp, <2 x double> %val, <2 x double> zeroinitializer
+  ret <2 x double> %ret
+}
+
+define <2 x double> @f6(<2 x double> %val) {
+; CHECK-LABEL: f6:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfmindb %v24, %v24, %v0, 1
+; CHECK-NEXT: br %r14
+  %cmp = fcmp ult <2 x double> %val,  zeroinitializer
+  %ret = select <2 x i1> %cmp, <2 x double> %val, <2 x double> zeroinitializer
+  ret <2 x double> %ret
+}
+
+define <4 x float> @f7(<4 x float> %val) {
+; CHECK-LABEL: f7:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfmaxsb %v24, %v24, %v0, 1
+; CHECK-NEXT: br %r14
+  %cmp = fcmp ugt <4 x float> %val,  zeroinitializer
+  %ret = select <4 x i1> %cmp, <4 x float> %val, <4 x float> zeroinitializer
+  ret <4 x float> %ret
+}
+
+define <4 x float> @f8(<4 x float> %val) {
+; CHECK-LABEL: f8:
+; CHECK: vgbm %v0, 0
+; CHECK-NEXT: vfminsb %v24, %v24, %v0, 1
+; CHECK-NEXT: br %r14
+  %cmp = fcmp ult <4 x float> %val,  zeroinitializer
+  %ret = select <4 x i1> %cmp, <4 x float> %val, <4 x float> zeroinitializer
+  ret <4 x float> %ret
+}