[llvm] 042f22b - [InstCombine] Add exact shift tests missed in D88475

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-09-29T15:24:59+01:00
New Revision: 042f22bda5d3e2851205781f0b921cc810bb6dcb

URL: https://github.com/llvm/llvm-project/commit/042f22bda5d3e2851205781f0b921cc810bb6dcb
DIFF: https://github.com/llvm/llvm-project/commit/042f22bda5d3e2851205781f0b921cc810bb6dcb.diff

LOG: [InstCombine] Add exact shift tests missed in D88475

I missed the post-LGTM comment from @lebedev.ri

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/test/Transforms/InstCombine/cast.ll b/llvm/test/Transforms/InstCombine/cast.ll
index 1d3d006ad238..db6b550f5faa 100644
--- a/llvm/test/Transforms/InstCombine/cast.ll
+++ b/llvm/test/Transforms/InstCombine/cast.ll
@@ -1546,6 +1546,17 @@ define i8 @trunc_lshr_sext(i8 %A) {
   ret i8 %D
 }
 
+define i8 @trunc_lshr_sext_exact(i8 %A) {
+; ALL-LABEL: @trunc_lshr_sext_exact(
+; ALL-NEXT:    [[D:%.*]] = ashr i8 [[A:%.*]], 6
+; ALL-NEXT:    ret i8 [[D]]
+;
+  %B = sext i8 %A to i32
+  %C = lshr exact i32 %B, 6
+  %D = trunc i32 %C to i8
+  ret i8 %D
+}
+
 define <2 x i8> @trunc_lshr_sext_uniform(<2 x i8> %A) {
 ; ALL-LABEL: @trunc_lshr_sext_uniform(
 ; ALL-NEXT:    [[D:%.*]] = ashr <2 x i8> [[A:%.*]], <i8 6, i8 6>
@@ -1705,6 +1716,18 @@ define i8 @trunc_lshr_sext_wide_input(i16 %A) {
   ret i8 %D
 }
 
+define i8 @trunc_lshr_sext_wide_input_exact(i16 %A) {
+; ALL-LABEL: @trunc_lshr_sext_wide_input_exact(
+; ALL-NEXT:    [[TMP1:%.*]] = ashr i16 [[A:%.*]], 9
+; ALL-NEXT:    [[D:%.*]] = trunc i16 [[TMP1]] to i8
+; ALL-NEXT:    ret i8 [[D]]
+;
+  %B = sext i16 %A to i32
+  %C = lshr exact i32 %B, 9
+  %D = trunc i32 %C to i8
+  ret i8 %D
+}
+
 define <2 x i8> @trunc_lshr_sext_wide_input_uses1(<2 x i16> %A) {
 ; ALL-LABEL: @trunc_lshr_sext_wide_input_uses1(
 ; ALL-NEXT:    [[B:%.*]] = sext <2 x i16> [[A:%.*]] to <2 x i32>