[llvm] [InstCombine] Pull extract through broadcast (PR #143380)

[Simon Pilgrim via llvm-commits]

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@@ -0,0 +1,52 @@
+; RUN: opt -passes=instcombine -S < %s | FileCheck %s
+
+define float @extract_from_zero_init_shuffle(<2 x float> %1, i64 %idx) {
+; CHECK-LABEL: @extract_from_zero_init_shuffle(
+; CHECK-NEXT:    [[TMP1:%.*]] = extractelement <2 x float> [[W:%.*]], i64 0
+; CHECK-NEXT:    ret float [[TMP1]]
+;
+  %3 = shufflevector <2 x float> %1, <2 x float> poison, <4 x i32> zeroinitializer
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RKSimon wrote:

(style) avoid using numbers for variable names (%vec, %shuffle and %extract would be better)

https://github.com/llvm/llvm-project/pull/143380