[llvm] [InstCombine] Resolve TODO: Remove one-time check if other logic operand (Y) is constant (PR #77973)

[Jessica Clarke via llvm-commits]

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@@ -433,9 +433,9 @@ define i8 @shl_sub(i8 %x, i8 %y) {
 define i8 @shl_sub_multiuse(i8 %x) {
 ; CHECK-LABEL: @shl_sub_multiuse(
 ; CHECK-NEXT:    [[SH0:%.*]] = shl i8 [[X:%.*]], 3
-; CHECK-NEXT:    [[R:%.*]] = sub i8 [[SH0]], 42 ; constant operand on the 'sub'
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jrtc27 wrote:

Uh, did update_llc_test_checks.py really add that comment?...

https://github.com/llvm/llvm-project/pull/77973