[llvm-branch-commits] [llvm] [ConstantFolding] Add constant folding for mask.beforefirst (PR #234472)

[Paul Walker via llvm-branch-commits]

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@@ -0,0 +1,58 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt -p instsimplify -S < %s | FileCheck %s
+
+define <4 x i1> @v4i1_zero() {
+; CHECK-LABEL: define <4 x i1> @v4i1_zero() {
+; CHECK-NEXT:    ret <4 x i1> splat (i1 true)
+;
+  %res = call <4 x i1> @llvm.mask.beforefirst(<4 x i1> zeroinitializer)
+  ret <4 x i1> %res
+}
+
+define <4 x i1> @v4i1_ones() {
+; CHECK-LABEL: define <4 x i1> @v4i1_ones() {
+; CHECK-NEXT:    ret <4 x i1> zeroinitializer
+;
+  %res = call <4 x i1> @llvm.mask.beforefirst(<4 x i1> splat (i1 true))
+  ret <4 x i1> %res
+}
+
+define <4 x i1> @v4i1() {
+; CHECK-LABEL: define <4 x i1> @v4i1() {
+; CHECK-NEXT:    ret <4 x i1> <i1 true, i1 false, i1 false, i1 false>
+;
+  %res = call <4 x i1> @llvm.mask.beforefirst(<4 x i1> <i1 false, i1 true, i1 false, i1 true>)
+  ret <4 x i1> %res
+}
+
+define <4 x i1> @v4i1_poison() {
+; CHECK-LABEL: define <4 x i1> @v4i1_poison() {
+; CHECK-NEXT:    ret <4 x i1> poison
+;
+  %res = call <4 x i1> @llvm.mask.beforefirst(<4 x i1> <i1 false, i1 true, i1 poison, i1 false>)
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paulwalker-arm wrote:

Not relevant to this PR but here the result can be well defined? Just something to consider if we find the current definition hampers usage. Specially I'm thinking once we have better support for speculative loads.

https://github.com/llvm/llvm-project/pull/234472