[X86] Exclude invalid element types for bitcast/broadcast folding.

It looks like the fold introduced in 63f3383 can cause crashes
if the type of the bitcasted value is not a valid vector element type,
like x86_mmx.

To resolve the crash, reject invalid vector element types. The way it is
done in the patch is a bit clunky. Perhaps there's a better way to
check?

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D104792

Author: fhahn

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -37487,7 +37487,9 @@ static SDValue combineTargetShuffle(SDValue N, SelectionDAG &DAG,
     // 32-bit targets have to bitcast i64 to f64, so better to bitcast upward.
     if (Src.getOpcode() == ISD::BITCAST &&
         SrcVT.getScalarSizeInBits() == BCVT.getScalarSizeInBits() &&
-        DAG.getTargetLoweringInfo().isTypeLegal(BCVT)) {
+        DAG.getTargetLoweringInfo().isTypeLegal(BCVT) &&
+        FixedVectorType::isValidElementType(
+            BCVT.getScalarType().getTypeForEVT(*DAG.getContext()))) {
       EVT NewVT = EVT::getVectorVT(*DAG.getContext(), BCVT.getScalarType(),
                                    VT.getVectorNumElements());
       return DAG.getBitcast(VT, DAG.getNode(X86ISD::VBROADCAST, DL, NewVT, BC));

llvm/test/CodeGen/X86/avx-vbroadcast.ll

@@ -1,6 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -mtriple=i686-apple-darwin -mattr=+avx | FileCheck %s --check-prefix=X32
-; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=+avx | FileCheck %s --check-prefix=X64
+; RUN: llc < %s -mtriple=i686-apple-darwin -mattr='+avx,+mmx' | FileCheck %s --check-prefix=X32
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr='+avx,+mmx' | FileCheck %s --check-prefix=X64
 
 define <4 x i64> @A(i64* %ptr) nounwind uwtable readnone ssp {
 ; X32-LABEL: A:
@@ -972,6 +972,30 @@ define float @broadcast_lifetime() nounwind {
   ret float %9
 }
 
+define <8 x i16> @broadcast_x86_mmx(x86_mmx %tmp) nounwind {
+; X32-LABEL: broadcast_x86_mmx:
+; X32:       ## %bb.0: ## %bb
+; X32-NEXT:    subl $12, %esp
+; X32-NEXT:    movq %mm0, (%esp)
+; X32-NEXT:    vmovsd {{.*#+}} xmm0 = mem[0],zero
+; X32-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,1,0,1]
+; X32-NEXT:    addl $12, %esp
+; X32-NEXT:    retl
+;
+; X64-LABEL: broadcast_x86_mmx:
+; X64:       ## %bb.0: ## %bb
+; X64-NEXT:    movdq2q %xmm0, %mm0
+; X64-NEXT:    movq2dq %mm0, %xmm0
+; X64-NEXT:    vpermilps {{.*#+}} xmm0 = xmm0[0,1,0,1]
+; X64-NEXT:    retq
+bb:
+  %tmp1 = bitcast x86_mmx %tmp to i64
+  %tmp2 = insertelement <2 x i64> undef, i64 %tmp1, i32 0
+  %tmp3 = bitcast <2 x i64> %tmp2 to <8 x i16>
+  %tmp4 = shufflevector <8 x i16> %tmp3, <8 x i16> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 0, i32 1, i32 2, i32 3>
+  ret <8 x i16> %tmp4
+}
+
 declare void @gfunc(<4 x float>*)
 declare void @llvm.lifetime.start.p0i8(i64, i8*)
 declare void @llvm.lifetime.end.p0i8(i64, i8*)

llvm/test/CodeGen/X86/avx2-vbroadcast.ll

@@ -1,8 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -mtriple=i686-apple-darwin -mattr=+avx2 | FileCheck %s --check-prefix=X32 --check-prefix=X32-AVX2
-; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=+avx2 | FileCheck %s --check-prefix=X64 --check-prefix=X64-AVX2
-; RUN: llc < %s -mtriple=i686-apple-darwin -mattr=+avx512vl,+avx512dq | FileCheck %s --check-prefix=X32 --check-prefix=X32-AVX512VL
-; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=+avx512vl,+avx512dq | FileCheck %s --check-prefix=X64 --check-prefix=X64-AVX512VL
+; RUN: llc < %s -mtriple=i686-apple-darwin -mattr=+avx2,+mmx | FileCheck %s --check-prefix=X32 --check-prefix=X32-AVX2
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=+avx2,+mmx | FileCheck %s --check-prefix=X64 --check-prefix=X64-AVX2
+; RUN: llc < %s -mtriple=i686-apple-darwin -mattr=+avx512vl,+avx512dq,+mmx | FileCheck %s --check-prefix=X32 --check-prefix=X32-AVX512VL
+; RUN: llc < %s -mtriple=x86_64-apple-darwin -mattr=+avx512vl,+avx512dq,+mmx | FileCheck %s --check-prefix=X64 --check-prefix=X64-AVX512VL
 
 define <16 x i8> @BB16(i8* %ptr) nounwind uwtable readnone ssp {
 ; X32-LABEL: BB16:
@@ -1448,3 +1448,34 @@ eintry:
   store <4 x i64> %splat.splat, <4 x i64>* %__b.addr.i, align 16
   ret void
 }
+
+define <8 x i16> @broadcast_x86_mmx(x86_mmx %tmp) nounwind {
+; X32-LABEL: broadcast_x86_mmx:
+; X32:       ## %bb.0: ## %bb
+; X32-NEXT:    subl $12, %esp
+; X32-NEXT:    movq %mm0, (%esp)
+; X32-NEXT:    vmovddup {{.*#+}} xmm0 = mem[0,0]
+; X32-NEXT:    addl $12, %esp
+; X32-NEXT:    retl
+;
+; X64-AVX2-LABEL: broadcast_x86_mmx:
+; X64-AVX2:       ## %bb.0: ## %bb
+; X64-AVX2-NEXT:    movdq2q %xmm0, %mm0
+; X64-AVX2-NEXT:    movq %mm0, %rax
+; X64-AVX2-NEXT:    vmovq %rax, %xmm0
+; X64-AVX2-NEXT:    vpbroadcastq %xmm0, %xmm0
+; X64-AVX2-NEXT:    retq
+;
+; X64-AVX512VL-LABEL: broadcast_x86_mmx:
+; X64-AVX512VL:       ## %bb.0: ## %bb
+; X64-AVX512VL-NEXT:    movdq2q %xmm0, %mm0
+; X64-AVX512VL-NEXT:    movq %mm0, %rax
+; X64-AVX512VL-NEXT:    vpbroadcastq %rax, %xmm0
+; X64-AVX512VL-NEXT:    retq
+bb:
+  %tmp1 = bitcast x86_mmx %tmp to i64
+  %tmp2 = insertelement <2 x i64> undef, i64 %tmp1, i32 0
+  %tmp3 = bitcast <2 x i64> %tmp2 to <8 x i16>
+  %tmp4 = shufflevector <8 x i16> %tmp3, <8 x i16> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 0, i32 1, i32 2, i32 3>
+  ret <8 x i16> %tmp4
+}