[FastISel] Bail out of selectGetElementPtr for vector GEPs.

The code that decomposes the GEP into ADD/MUL doesn't work properly
for vector GEPs. It can create bad COPY instructions or possibly
assert.

For now just bail out to SelectionDAG.

Fixes PR45906

(cherry picked from commit 4208ea3)

Author: topperc

llvm/lib/CodeGen/SelectionDAG/FastISel.cpp

@@ -690,6 +690,12 @@ bool FastISel::selectGetElementPtr(const User *I) {
   Register N = getRegForValue(I->getOperand(0));
   if (!N) // Unhandled operand. Halt "fast" selection and bail.
     return false;
+
+  // FIXME: The code below does not handle vector GEPs. Halt "fast" selection
+  // and bail.
+  if (isa<VectorType>(I->getType()))
+    return false;
+
   bool NIsKill = hasTrivialKill(I->getOperand(0));
 
   // Keep a running tab of the total offset to coalesce multiple N = N + Offset

llvm/test/CodeGen/X86/masked_gather_scatter.ll

@@ -3319,3 +3319,51 @@ define void @scatter_16i64_constant_indices(i32* %ptr, <16 x i1> %mask, <16 x i3
   call void @llvm.masked.scatter.v16i32.v16p0i32(<16 x i32> %src0, <16 x i32*> %gep, i32 4, <16 x i1> %mask)
   ret void
 }
+
+%struct.foo = type { i8*, i64, i16, i16, i32 }
+
+; This used to cause fast-isel to generate bad copy instructions that would
+; cause an error in copyPhysReg.
+define <8 x i64> @pr45906(<8 x %struct.foo*> %ptr) {
+; KNL_64-LABEL: pr45906:
+; KNL_64:       # %bb.0: # %bb
+; KNL_64-NEXT:    vpaddq {{.*}}(%rip){1to8}, %zmm0, %zmm1
+; KNL_64-NEXT:    kxnorw %k0, %k0, %k1
+; KNL_64-NEXT:    vpgatherqq (,%zmm1), %zmm0 {%k1}
+; KNL_64-NEXT:    retq
+;
+; KNL_32-LABEL: pr45906:
+; KNL_32:       # %bb.0: # %bb
+; KNL_32-NEXT:    vpbroadcastd {{.*#+}} ymm1 = [4,4,4,4,4,4,4,4]
+; KNL_32-NEXT:    vpaddd %ymm1, %ymm0, %ymm1
+; KNL_32-NEXT:    kxnorw %k0, %k0, %k1
+; KNL_32-NEXT:    vpgatherdq (,%ymm1), %zmm0 {%k1}
+; KNL_32-NEXT:    retl
+;
+; SKX_SMALL-LABEL: pr45906:
+; SKX_SMALL:       # %bb.0: # %bb
+; SKX_SMALL-NEXT:    vpaddq {{.*}}(%rip){1to8}, %zmm0, %zmm1
+; SKX_SMALL-NEXT:    kxnorw %k0, %k0, %k1
+; SKX_SMALL-NEXT:    vpgatherqq (,%zmm1), %zmm0 {%k1}
+; SKX_SMALL-NEXT:    retq
+;
+; SKX_LARGE-LABEL: pr45906:
+; SKX_LARGE:       # %bb.0: # %bb
+; SKX_LARGE-NEXT:    movabsq ${{\.LCPI.*}}, %rax
+; SKX_LARGE-NEXT:    vpaddq (%rax){1to8}, %zmm0, %zmm1
+; SKX_LARGE-NEXT:    kxnorw %k0, %k0, %k1
+; SKX_LARGE-NEXT:    vpgatherqq (,%zmm1), %zmm0 {%k1}
+; SKX_LARGE-NEXT:    retq
+;
+; SKX_32-LABEL: pr45906:
+; SKX_32:       # %bb.0: # %bb
+; SKX_32-NEXT:    vpaddd {{\.LCPI.*}}{1to8}, %ymm0, %ymm1
+; SKX_32-NEXT:    kxnorw %k0, %k0, %k1
+; SKX_32-NEXT:    vpgatherdq (,%ymm1), %zmm0 {%k1}
+; SKX_32-NEXT:    retl
+bb:
+  %tmp = getelementptr inbounds %struct.foo, <8 x %struct.foo*> %ptr, i64 0, i32 1
+  %tmp1 = call <8 x i64> @llvm.masked.gather.v8i64.v8p0i64(<8 x i64*> %tmp, i32 8, <8 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, <8 x i64> undef)
+  ret <8 x i64> %tmp1
+}
+declare <8 x i64> @llvm.masked.gather.v8i64.v8p0i64(<8 x i64*>, i32, <8 x i1>, <8 x i64>)