ARM ISel: Don't create illegal types during LowerMUL

The transformation happening here is that we want to turn a
"mul(ext(X), ext(X))" into a "vmull(X, X)", stripping off the extension. We have
to make sure that X still has a valid vector type - possibly recreate an
extension to a smaller type. In case of a extload of a memory type smaller than
64 bit we used create a ext(load()). The problem with doing this - instead of
recreating an extload - is that an illegal type is exposed.

This patch fixes this by creating extloads instead of ext(load()) sequences.

Fixes PR15970.

radar://13871383

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181842 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 24 insertions, 0 deletions

diff --git a/test/CodeGen/ARM/vmul.ll b/test/CodeGen/ARM/vmul.ll
index 74628f0c5c..eb5ad8f0c3 100644
--- a/test/CodeGen/ARM/vmul.ll
+++ b/test/CodeGen/ARM/vmul.ll
@@ -599,3 +599,27 @@ for.end179:                                       ; preds = %for.cond.loopexit,
 declare <8 x i16> @llvm.arm.neon.vrshiftu.v8i16(<8 x i16>, <8 x i16>) nounwind readnone
 declare <8 x i16> @llvm.arm.neon.vqsubu.v8i16(<8 x i16>, <8 x i16>) nounwind readnone
 declare <8 x i8> @llvm.arm.neon.vqmovnu.v8i8(<8 x i16>) nounwind readnone
+
+; vmull lowering would create a zext(v4i8 load()) instead of a zextload(v4i8),
+; creating an illegal type during legalization and causing an assert.
+; PR15970
+define void @no_illegal_types_vmull_sext(<4 x i32> %a) {
+entry:
+  %wide.load283.i = load <4 x i8>* undef, align 1
+  %0 = sext <4 x i8> %wide.load283.i to <4 x i32>
+  %1 = sub nsw <4 x i32> %0, %a
+  %2 = mul nsw <4 x i32> %1, %1
+  %predphi290.v.i = select <4 x i1> undef, <4 x i32> undef, <4 x i32> %2
+  store <4 x i32> %predphi290.v.i, <4 x i32>* undef, align 4
+  ret void
+}
+define void @no_illegal_types_vmull_zext(<4 x i32> %a) {
+entry:
+  %wide.load283.i = load <4 x i8>* undef, align 1
+  %0 = zext <4 x i8> %wide.load283.i to <4 x i32>
+  %1 = sub nsw <4 x i32> %0, %a
+  %2 = mul nsw <4 x i32> %1, %1
+  %predphi290.v.i = select <4 x i1> undef, <4 x i32> undef, <4 x i32> %2
+  store <4 x i32> %predphi290.v.i, <4 x i32>* undef, align 4
+  ret void
+}