[InstCombine] handle zero constant vectors for LE/GE comparisons too

Enhancement to: http://reviews.llvm.org/rL269426
With discussion in: http://reviews.llvm.org/D17859

This should complete the fixes for: PR26701, PR26819:
https://llvm.org/bugs/show_bug.cgi?id=26701
https://llvm.org/bugs/show_bug.cgi?id=26819
 

llvm-svn: 269439

1 files changed, 37 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/icmp-vec.ll b/llvm/test/Transforms/InstCombine/icmp-vec.ll
index f8416cc6e95..df653caa56d 100644
--- a/llvm/test/Transforms/InstCombine/icmp-vec.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-vec.ll
@@ -42,6 +42,43 @@ define <2 x i1> @ule(<2 x i8> %x) {
   ret <2 x i1> %cmp
 }
 
+; Zeros are special: they're ConstantAggregateZero.
+
+define <2 x i1> @sge_zero(<2 x i8> %x) {
+; CHECK-LABEL: @sge_zero(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt <2 x i8> %x, <i8 -1, i8 -1>
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %cmp = icmp sge <2 x i8> %x, <i8 0, i8 0>
+  ret <2 x i1> %cmp
+}
+
+define <2 x i1> @uge_zero(<2 x i8> %x) {
+; CHECK-LABEL: @uge_zero(
+; CHECK-NEXT:    ret <2 x i1> <i1 true, i1 true>
+;
+  %cmp = icmp uge <2 x i8> %x, <i8 0, i8 0>
+  ret <2 x i1> %cmp
+}
+
+define <2 x i1> @sle_zero(<2 x i8> %x) {
+; CHECK-LABEL: @sle_zero(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt <2 x i8> %x, <i8 1, i8 1>
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %cmp = icmp sle <2 x i8> %x, <i8 0, i8 0>
+  ret <2 x i1> %cmp
+}
+
+define <2 x i1> @ule_zero(<2 x i8> %x) {
+; CHECK-LABEL: @ule_zero(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ult <2 x i8> %x, <i8 1, i8 1>
+; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+;
+  %cmp = icmp ule <2 x i8> %x, <i8 0, i8 0>
+  ret <2 x i1> %cmp
+}
+
 ; Weird types are ConstantVectors, not ConstantDataVectors. For an i3 type:
 ; Signed min = -4
 ; Unsigned min = 0