[DAGCombiner] Fix PR25763 - vector comparison constant folding + sign-extension
PR25763 demonstrated an issue with D14683 - vector comparison constant folding only works for i1 results, so we need to split off the sign-extension of the result to the required type. Luckily this can be done with the existing type legalization code.
llvm-svn: 255289
diff --git a/llvm/test/CodeGen/AArch64/fold-constants.ll b/llvm/test/CodeGen/AArch64/fold-constants.ll
index 3f70f0a..c0fec4d 100644
--- a/llvm/test/CodeGen/AArch64/fold-constants.ll
+++ b/llvm/test/CodeGen/AArch64/fold-constants.ll
@@ -16,3 +16,19 @@
%vget_lane = extractelement <1 x i64> %4, i32 0
ret i64 %vget_lane
}
+
+; PR25763 - folding constant vector comparisons with sign-extended result
+define <8 x i16> @dotests_458() {
+; CHECK-LABEL: dotests_458
+; CHECK: movi d0, #0x00000000ff0000
+; CHECK-NEXT: sshll v0.8h, v0.8b, #0
+; CHECK-NEXT: ret
+entry:
+ %vclz_v.i = call <8 x i8> @llvm.ctlz.v8i8(<8 x i8> <i8 127, i8 38, i8 -1, i8 -128, i8 127, i8 0, i8 0, i8 0>, i1 false) #6
+ %vsra_n = lshr <8 x i8> %vclz_v.i, <i8 5, i8 5, i8 5, i8 5, i8 5, i8 5, i8 5, i8 5>
+ %name_6 = or <8 x i8> %vsra_n, <i8 127, i8 -128, i8 -1, i8 67, i8 84, i8 127, i8 -1, i8 0>
+ %cmp.i603 = icmp slt <8 x i8> %name_6, <i8 -57, i8 -128, i8 127, i8 -128, i8 -1, i8 0, i8 -1, i8 -1>
+ %vmovl.i4.i = sext <8 x i1> %cmp.i603 to <8 x i16>
+ ret <8 x i16> %vmovl.i4.i
+}
+declare <8 x i8> @llvm.ctlz.v8i8(<8 x i8>, i1)