[llvm] 8e9a8dc - [InstCombine] Add tests showing failure to fold mul(abs(x),abs(x)) -> mul(x,x) (PR39476)

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-05-04T10:24:18+01:00
New Revision: 8e9a8dc185be14246172ffc9b6b8c61a9d8d7cc4

URL: https://github.com/llvm/llvm-project/commit/8e9a8dc185be14246172ffc9b6b8c61a9d8d7cc4
DIFF: https://github.com/llvm/llvm-project/commit/8e9a8dc185be14246172ffc9b6b8c61a9d8d7cc4.diff

LOG: [InstCombine] Add tests showing failure to fold mul(abs(x),abs(x)) -> mul(x,x) (PR39476)

Includes abs() and nabs() variants

Added: 
    

Modified: 
    llvm/test/Transforms/InstCombine/mul.ll

Removed: 
    


################################################################################
diff  --git a/llvm/test/Transforms/InstCombine/mul.ll b/llvm/test/Transforms/InstCombine/mul.ll
index 3fc1cc54ea3a..32a19604e765 100644
--- a/llvm/test/Transforms/InstCombine/mul.ll
+++ b/llvm/test/Transforms/InstCombine/mul.ll
@@ -606,3 +606,95 @@ define i32 @mul_div_select(i32 %x, i32 %y, i1 %c) {
   %mul = mul i32 %sel, %y
   ret i32 %mul
 }
+
+; fold mul(abs(x),abs(x)) -> mul(x,x)
+define i31 @combine_mul_abs_i31(i31 %0) {
+; CHECK-LABEL: @combine_mul_abs_i31(
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i31 [[TMP0:%.*]], 0
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i31 0, [[TMP0]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[C]], i31 [[S]], i31 [[TMP0]]
+; CHECK-NEXT:    [[M:%.*]] = mul i31 [[R]], [[R]]
+; CHECK-NEXT:    ret i31 [[M]]
+;
+  %c = icmp slt i31 %0, 0
+  %s = sub nsw i31 0, %0
+  %r = select i1 %c, i31 %s, i31 %0
+  %m = mul i31 %r, %r
+  ret i31 %m
+}
+
+define i32 @combine_mul_abs_i32(i32 %0) {
+; CHECK-LABEL: @combine_mul_abs_i32(
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i32 [[TMP0:%.*]], 0
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 0, [[TMP0]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[C]], i32 [[S]], i32 [[TMP0]]
+; CHECK-NEXT:    [[M:%.*]] = mul i32 [[R]], [[R]]
+; CHECK-NEXT:    ret i32 [[M]]
+;
+  %c = icmp slt i32 %0, 0
+  %s = sub nsw i32 0, %0
+  %r = select i1 %c, i32 %s, i32 %0
+  %m = mul i32 %r, %r
+  ret i32 %m
+}
+
+define <4 x i32> @combine_mul_abs_v4i32(<4 x i32> %0) {
+; CHECK-LABEL: @combine_mul_abs_v4i32(
+; CHECK-NEXT:    [[C:%.*]] = icmp slt <4 x i32> [[TMP0:%.*]], zeroinitializer
+; CHECK-NEXT:    [[S:%.*]] = sub nsw <4 x i32> zeroinitializer, [[TMP0]]
+; CHECK-NEXT:    [[R:%.*]] = select <4 x i1> [[C]], <4 x i32> [[S]], <4 x i32> [[TMP0]]
+; CHECK-NEXT:    [[M:%.*]] = mul <4 x i32> [[R]], [[R]]
+; CHECK-NEXT:    ret <4 x i32> [[M]]
+;
+  %c = icmp slt <4 x i32> %0, zeroinitializer
+  %s = sub nsw <4 x i32> zeroinitializer, %0
+  %r = select <4 x i1> %c, <4 x i32> %s, <4 x i32> %0
+  %m = mul <4 x i32> %r, %r
+  ret <4 x i32> %m
+}
+
+; fold mul(nabs(x),nabs(x)) -> mul(x,x)
+define i31 @combine_mul_nabs_i31(i31 %0) {
+; CHECK-LABEL: @combine_mul_nabs_i31(
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i31 [[TMP0:%.*]], 0
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i31 0, [[TMP0]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[C]], i31 [[TMP0]], i31 [[S]]
+; CHECK-NEXT:    [[M:%.*]] = mul i31 [[R]], [[R]]
+; CHECK-NEXT:    ret i31 [[M]]
+;
+  %c = icmp slt i31 %0, 0
+  %s = sub nsw i31 0, %0
+  %r = select i1 %c, i31 %0, i31 %s
+  %m = mul i31 %r, %r
+  ret i31 %m
+}
+
+define i32 @combine_mul_nabs_i32(i32 %0) {
+; CHECK-LABEL: @combine_mul_nabs_i32(
+; CHECK-NEXT:    [[C:%.*]] = icmp slt i32 [[TMP0:%.*]], 0
+; CHECK-NEXT:    [[S:%.*]] = sub nsw i32 0, [[TMP0]]
+; CHECK-NEXT:    [[R:%.*]] = select i1 [[C]], i32 [[TMP0]], i32 [[S]]
+; CHECK-NEXT:    [[M:%.*]] = mul i32 [[R]], [[R]]
+; CHECK-NEXT:    ret i32 [[M]]
+;
+  %c = icmp slt i32 %0, 0
+  %s = sub nsw i32 0, %0
+  %r = select i1 %c, i32 %0, i32 %s
+  %m = mul i32 %r, %r
+  ret i32 %m
+}
+
+define <4 x i32> @combine_mul_nabs_v4i32(<4 x i32> %0) {
+; CHECK-LABEL: @combine_mul_nabs_v4i32(
+; CHECK-NEXT:    [[C:%.*]] = icmp slt <4 x i32> [[TMP0:%.*]], zeroinitializer
+; CHECK-NEXT:    [[S:%.*]] = sub nsw <4 x i32> zeroinitializer, [[TMP0]]
+; CHECK-NEXT:    [[R:%.*]] = select <4 x i1> [[C]], <4 x i32> [[TMP0]], <4 x i32> [[S]]
+; CHECK-NEXT:    [[M:%.*]] = mul <4 x i32> [[R]], [[R]]
+; CHECK-NEXT:    ret <4 x i32> [[M]]
+;
+  %c = icmp slt <4 x i32> %0, zeroinitializer
+  %s = sub nsw <4 x i32> zeroinitializer, %0
+  %r = select <4 x i1> %c, <4 x i32> %0, <4 x i32> %s
+  %m = mul <4 x i32> %r, %r
+  ret <4 x i32> %m
+}