[llvm] [InstCombine] Fold adds + shifts with nuw flags (PR #88193)
Matt Arsenault via llvm-commits
llvm-commits at lists.llvm.org
Thu May 2 10:51:24 PDT 2024
================
@@ -360,8 +360,58 @@ define <3 x i14> @mul_splat_fold_vec(<3 x i14> %x) {
ret <3 x i14> %t
}
+define i32 @shl_add_lshr_flag_preservation(i32 %x, i32 %c, i32 %y) {
+; CHECK-LABEL: @shl_add_lshr_flag_preservation(
+; CHECK-NEXT: [[TMP1:%.*]] = lshr exact i32 [[Y:%.*]], [[C:%.*]]
+; CHECK-NEXT: [[LSHR:%.*]] = add nuw nsw i32 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT: ret i32 [[LSHR]]
+;
+ %shl = shl nuw i32 %x, %c
+ %add = add nuw nsw i32 %shl, %y
+ %lshr = lshr exact i32 %add, %c
+ ret i32 %lshr
+}
+
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arsenm wrote:
Extra newline
https://github.com/llvm/llvm-project/pull/88193
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