[llvm] [InstCombine] Fold `select (A &/| B), T, F` if `select B, T, F` is foldable (PR #76621)

[Nikita Popov via llvm-commits]

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@@ -303,7 +303,7 @@ define i1 @and_logic_and_logic_or_not_one_use(i1 %c, i1 %a, i1 %b) {
 ; CHECK-LABEL: @and_logic_and_logic_or_not_one_use(
 ; CHECK-NEXT:    [[AC:%.*]] = and i1 [[A:%.*]], [[C:%.*]]
 ; CHECK-NEXT:    [[BC:%.*]] = select i1 [[B:%.*]], i1 [[C]], i1 false
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[BC]], i1 true, i1 [[AC]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[B]], i1 [[C]], i1 [[AC]]
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nikic wrote:

I'd consider this a regression, as logical or is more canonical. Skip if the outer select is already a logical op?

https://github.com/llvm/llvm-project/pull/76621