add tests for PR28153

llvm-svn: 273936

1 files changed, 76 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/div.ll b/llvm/test/Transforms/InstCombine/div.ll
index 2b7c907f177..4ad7005da20 100644
--- a/llvm/test/Transforms/InstCombine/div.ll
+++ b/llvm/test/Transforms/InstCombine/div.ll
@@ -408,3 +408,79 @@ lor.end:                                          ; preds = %lor.rhs, %entry
   %div = sdiv i32 %t.0, 2
   ret i32 %div
 }
+
+; FIXME:
+; We can perform the division in the smaller type.
+
+define i32 @shrink(i8 %x) {
+; CHECK-LABEL: @shrink(
+; CHECK-NEXT:    [[CONV:%.*]] = sext i8 %x to i32
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i32 [[CONV]], 127
+; CHECK-NEXT:    ret i32 [[DIV]]
+;
+  %conv = sext i8 %x to i32
+  %div = sdiv i32 %conv, 127
+  ret i32 %div
+}
+
+; Division in the smaller type can lead to more optimizations.
+
+define i32 @zap(i8 %x) {
+; CHECK-LABEL: @zap(
+; CHECK-NEXT:    [[CONV:%.*]] = sext i8 %x to i32
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i32 [[CONV]], -128
+; CHECK-NEXT:    ret i32 [[DIV]]
+;
+  %conv = sext i8 %x to i32
+  %div = sdiv i32 %conv, -128
+  ret i32 %div
+}
+
+; Splat constant divisors should get the same folds.
+
+define <3 x i32> @shrink_vec(<3 x i8> %x) {
+; CHECK-LABEL: @shrink_vec(
+; CHECK-NEXT:    [[CONV:%.*]] = sext <3 x i8> %x to <3 x i32>
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv <3 x i32> [[CONV]], <i32 127, i32 127, i32 127>
+; CHECK-NEXT:    ret <3 x i32> [[DIV]]
+;
+  %conv = sext <3 x i8> %x to <3 x i32>
+  %div = sdiv <3 x i32> %conv, <i32 127, i32 127, i32 127>
+  ret <3 x i32> %div
+}
+
+define <2 x i32> @zap_vec(<2 x i8> %x) {
+; CHECK-LABEL: @zap_vec(
+; CHECK-NEXT:    [[CONV:%.*]] = sext <2 x i8> %x to <2 x i32>
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv <2 x i32> [[CONV]], <i32 -128, i32 -128>
+; CHECK-NEXT:    ret <2 x i32> [[DIV]]
+;
+  %conv = sext <2 x i8> %x to <2 x i32>
+  %div = sdiv <2 x i32> %conv, <i32 -128, i32 -128>
+  ret <2 x i32> %div
+}
+
+; But we can't do this if the signed constant won't fit in the original type.
+
+define i32 @shrink_no(i8 %x) {
+; CHECK-LABEL: @shrink_no(
+; CHECK-NEXT:    [[CONV:%.*]] = sext i8 %x to i32
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i32 [[CONV]], 128
+; CHECK-NEXT:    ret i32 [[DIV]]
+;
+  %conv = sext i8 %x to i32
+  %div = sdiv i32 %conv, 128
+  ret i32 %div
+}
+
+define i32 @shrink_no2(i8 %x) {
+; CHECK-LABEL: @shrink_no2(
+; CHECK-NEXT:    [[CONV:%.*]] = sext i8 %x to i32
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i32 [[CONV]], -129
+; CHECK-NEXT:    ret i32 [[DIV]]
+;
+  %conv = sext i8 %x to i32
+  %div = sdiv i32 %conv, -129
+  ret i32 %div
+}
+