[llvm] [InstCombine] Fold `(trunc X)` into `X & Mask` inside `decomposeBitTestICmp` (PR #171195)

[Tirthankar Mazumder via llvm-commits]

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@@ -3721,3 +3721,19 @@ define i1 @merge_range_check_or(i8 %a) {
   %and = or i1 %cmp1, %cmp2
   ret i1 %and
 }
+
+; Just a very complicated way of checking if v1 == 0.
+define i1 @complicated_zero_equality_test(i64 %v1) {
+; CHECK-LABEL: @complicated_zero_equality_test(
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wermos wrote:

Oops, I forgot to run `llvm/utils/update_test_checks.py`. I'll do that now.

https://github.com/llvm/llvm-project/pull/171195