[VectorCombine][X86] Add tests showing failure to push a shuffle through a fma with multiple constants (llvm#170458)

Despite 2 of the 3 arguments of the fma intrinsics calls being constant
(free shuffle), foldShuffleOfIntrinsics fails to fold the shuffle
through

Author: RKSimon

llvm/test/Transforms/VectorCombine/X86/shuffle-of-fma-const.ll

@@ -0,0 +1,49 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt < %s -passes=vector-combine -S -mtriple=x86_64-- -mcpu=x86-64    | FileCheck %s --check-prefixes=CHECK,SSE
+; RUN: opt < %s -passes=vector-combine -S -mtriple=x86_64-- -mcpu=x86-64-v3 | FileCheck %s --check-prefixes=CHECK,AVX
+
+define <4 x float> @shuffle_fma_const_chain(<4 x float> %a0) {
+; CHECK-LABEL: define <4 x float> @shuffle_fma_const_chain(
+; CHECK-SAME: <4 x float> [[A0:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:    [[F:%.*]] = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> [[A0]], <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+; CHECK-NEXT:    [[RES:%.*]] = shufflevector <4 x float> [[F]], <4 x float> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+; CHECK-NEXT:    ret <4 x float> [[RES]]
+;
+  %f = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> %a0, <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+  %res = shufflevector <4 x float> %f, <4 x float> poison, <4 x i32> <i32 3, i32 2, i32 1, i32 0>
+  ret <4 x float> %res
+}
+
+define <8 x float> @concat_fma_const_chain(<4 x float> %a0, <4 x float> %a1) {
+; SSE-LABEL: define <8 x float> @concat_fma_const_chain(
+; SSE-SAME: <4 x float> [[A0:%.*]], <4 x float> [[A1:%.*]]) #[[ATTR0]] {
+; SSE-NEXT:    [[TMP1:%.*]] = shufflevector <4 x float> [[A0]], <4 x float> [[A1]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+; SSE-NEXT:    [[RES:%.*]] = call <8 x float> @llvm.fma.v8f32(<8 x float> [[TMP1]], <8 x float> splat (float 0x3F8DE8D040000000), <8 x float> splat (float 0xBFB3715EE0000000))
+; SSE-NEXT:    ret <8 x float> [[RES]]
+;
+; AVX-LABEL: define <8 x float> @concat_fma_const_chain(
+; AVX-SAME: <4 x float> [[A0:%.*]], <4 x float> [[A1:%.*]]) #[[ATTR0]] {
+; AVX-NEXT:    [[L:%.*]] = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> [[A0]], <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+; AVX-NEXT:    [[H:%.*]] = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> [[A1]], <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+; AVX-NEXT:    [[RES:%.*]] = shufflevector <4 x float> [[L]], <4 x float> [[H]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+; AVX-NEXT:    ret <8 x float> [[RES]]
+;
+  %l = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> %a0, <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+  %h = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> %a1, <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+  %res = shufflevector <4 x float> %l, <4 x float> %h, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+  ret <8 x float> %res
+}
+
+define <8 x float> @interleave_fma_const_chain(<4 x float> %a0, <4 x float> %a1) {
+; CHECK-LABEL: define <8 x float> @interleave_fma_const_chain(
+; CHECK-SAME: <4 x float> [[A0:%.*]], <4 x float> [[A1:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:    [[L:%.*]] = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> [[A0]], <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+; CHECK-NEXT:    [[H:%.*]] = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> [[A1]], <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+; CHECK-NEXT:    [[RES:%.*]] = shufflevector <4 x float> [[L]], <4 x float> [[H]], <8 x i32> <i32 0, i32 4, i32 1, i32 5, i32 2, i32 6, i32 3, i32 7>
+; CHECK-NEXT:    ret <8 x float> [[RES]]
+;
+  %l = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> %a0, <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+  %h = tail call noundef <4 x float> @llvm.fma.v4f32(<4 x float> %a1, <4 x float> splat (float 0x3F8DE8D040000000), <4 x float> splat (float 0xBFB3715EE0000000))
+  %res = shufflevector <4 x float> %l, <4 x float> %h, <8 x i32> <i32 0, i32 4, i32 1, i32 5, i32 2, i32 6, i32 3, i32 7>
+  ret <8 x float> %res
+}