[llvm] 88a9c18 - [InstCombine] add test for shl + demanded bits; NFC
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Sun Oct 3 07:39:26 PDT 2021
Author: Sanjay Patel
Date: 2021-10-03T10:35:59-04:00
New Revision: 88a9c1827e8dfd74aa2b2ba4f58ddf557b253c4e
URL: https://github.com/llvm/llvm-project/commit/88a9c1827e8dfd74aa2b2ba4f58ddf557b253c4e
DIFF: https://github.com/llvm/llvm-project/commit/88a9c1827e8dfd74aa2b2ba4f58ddf557b253c4e.diff
LOG: [InstCombine] add test for shl + demanded bits; NFC
This is a reduction of a test that would infinite loop with D110170.
Added:
Modified:
llvm/test/Transforms/InstCombine/shl-demand.ll
Removed:
################################################################################
diff --git a/llvm/test/Transforms/InstCombine/shl-demand.ll b/llvm/test/Transforms/InstCombine/shl-demand.ll
index 11c2de8e58d75..eca81cebe5cd4 100644
--- a/llvm/test/Transforms/InstCombine/shl-demand.ll
+++ b/llvm/test/Transforms/InstCombine/shl-demand.ll
@@ -98,3 +98,20 @@ define i8 @must_drop_poison(i32 %x, i32 %y) {
%t = trunc i32 %s to i8
ret i8 %t
}
+
+; This would infinite loop with D110170 / bb9333c3504a
+
+define i32 @f_t15_t01_t09(i40 %t2) {
+; CHECK-LABEL: @f_t15_t01_t09(
+; CHECK-NEXT: [[SH_DIFF:%.*]] = ashr i40 [[T2:%.*]], 15
+; CHECK-NEXT: [[TR_SH_DIFF:%.*]] = trunc i40 [[SH_DIFF]] to i32
+; CHECK-NEXT: [[SHL1:%.*]] = and i32 [[TR_SH_DIFF]], -65536
+; CHECK-NEXT: ret i32 [[SHL1]]
+;
+ %downscale = ashr i40 %t2, 31
+ %resize = trunc i40 %downscale to i32
+ %shl1 = shl i32 %resize, 16
+ %resize1 = ashr i32 %shl1, 16
+ %r = shl i32 %resize1, 31
+ ret i32 %shl1
+}
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