From 32b95a37083d1fee1a638e292be0aac9a98792fd Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Thu, 11 Apr 2024 10:05:53 +0100
Subject: [PATCH] [VectorCombine][X86] Extend shuffle(bitcast(x),bitcast(y))
 test coverage

As discussed on #87510 the intention is to fold shuffle(bitcast(x),bitcast(y)) -> bitcast(shuffle(x,y)), but it must not interfere with existing bitcast(shuffle(bitcast(x),bitcast(y))) folds.
---
 .../VectorCombine/X86/shuffle-of-casts.ll     | 67 ++++++++++++++++---
 1 file changed, 56 insertions(+), 11 deletions(-)

diff --git a/llvm/test/Transforms/VectorCombine/X86/shuffle-of-casts.ll b/llvm/test/Transforms/VectorCombine/X86/shuffle-of-casts.ll
index 2031c2d04c6018..60c6ff97c58b52 100644
--- a/llvm/test/Transforms/VectorCombine/X86/shuffle-of-casts.ll
+++ b/llvm/test/Transforms/VectorCombine/X86/shuffle-of-casts.ll
@@ -165,6 +165,51 @@ define <8 x double> @interleave_fpext_v4f32_v8f64(<4 x float> %a0, <4 x float> %
   ret <8 x double> %r
 }
 
+; TODO - bitcasts (same element count)
+
+define <8 x float> @concat_bitcast_v4i32_v8f32(<4 x i32> %a0, <4 x i32> %a1) {
+; CHECK-LABEL: @concat_bitcast_v4i32_v8f32(
+; CHECK-NEXT:    [[X0:%.*]] = bitcast <4 x i32> [[A0:%.*]] to <4 x float>
+; CHECK-NEXT:    [[X1:%.*]] = bitcast <4 x i32> [[A1:%.*]] to <4 x float>
+; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x float> [[X0]], <4 x float> [[X1]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+; CHECK-NEXT:    ret <8 x float> [[R]]
+;
+  %x0 = bitcast <4 x i32> %a0 to <4 x float>
+  %x1 = bitcast <4 x i32> %a1 to <4 x float>
+  %r = shufflevector <4 x float> %x0, <4 x float> %x1, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
+  ret <8 x float> %r
+}
+
+; TODO - bitcasts (lower element count)
+
+define <4 x double> @concat_bitcast_v8i16_v4f64(<8 x i16> %a0, <8 x i16> %a1) {
+; CHECK-LABEL: @concat_bitcast_v8i16_v4f64(
+; CHECK-NEXT:    [[X0:%.*]] = bitcast <8 x i16> [[A0:%.*]] to <2 x double>
+; CHECK-NEXT:    [[X1:%.*]] = bitcast <8 x i16> [[A1:%.*]] to <2 x double>
+; CHECK-NEXT:    [[R:%.*]] = shufflevector <2 x double> [[X0]], <2 x double> [[X1]], <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+; CHECK-NEXT:    ret <4 x double> [[R]]
+;
+  %x0 = bitcast <8 x i16> %a0 to <2 x double>
+  %x1 = bitcast <8 x i16> %a1 to <2 x double>
+  %r = shufflevector <2 x double> %x0, <2 x double> %x1, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
+  ret <4 x double> %r
+}
+
+; TODO - bitcasts (higher element count)
+
+define <16 x i16> @concat_bitcast_v4i32_v16i16(<4 x i32> %a0, <4 x i32> %a1) {
+; CHECK-LABEL: @concat_bitcast_v4i32_v16i16(
+; CHECK-NEXT:    [[X0:%.*]] = bitcast <4 x i32> [[A0:%.*]] to <8 x i16>
+; CHECK-NEXT:    [[X1:%.*]] = bitcast <4 x i32> [[A1:%.*]] to <8 x i16>
+; CHECK-NEXT:    [[R:%.*]] = shufflevector <8 x i16> [[X0]], <8 x i16> [[X1]], <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+; CHECK-NEXT:    ret <16 x i16> [[R]]
+;
+  %x0 = bitcast <4 x i32> %a0 to <8 x i16>
+  %x1 = bitcast <4 x i32> %a1 to <8 x i16>
+  %r = shufflevector <8 x i16> %x0, <8 x i16> %x1, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+  ret <16 x i16> %r
+}
+
 ; negative - multiuse
 
 define <8 x i16> @concat_trunc_v4i32_v8i16_multiuse(<4 x i32> %a0, <4 x i32> %a1, ptr %a2) {
@@ -182,19 +227,19 @@ define <8 x i16> @concat_trunc_v4i32_v8i16_multiuse(<4 x i32> %a0, <4 x i32> %a1
   ret <8 x i16> %r
 }
 
-; negative - bitcasts
+; negative - bitcasts (unscalable higher element count)
 
-define <8 x float> @concat_bitcast_v4i32_v8f32(<4 x i32> %a0, <4 x i32> %a1) {
-; CHECK-LABEL: @concat_bitcast_v4i32_v8f32(
-; CHECK-NEXT:    [[X0:%.*]] = bitcast <4 x i32> [[A0:%.*]] to <4 x float>
-; CHECK-NEXT:    [[X1:%.*]] = bitcast <4 x i32> [[A1:%.*]] to <4 x float>
-; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x float> [[X0]], <4 x float> [[X1]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT:    ret <8 x float> [[R]]
+define <16 x i16> @revpair_bitcast_v4i32_v16i16(<4 x i32> %a0, <4 x i32> %a1) {
+; CHECK-LABEL: @revpair_bitcast_v4i32_v16i16(
+; CHECK-NEXT:    [[X0:%.*]] = bitcast <4 x i32> [[A0:%.*]] to <8 x i16>
+; CHECK-NEXT:    [[X1:%.*]] = bitcast <4 x i32> [[A1:%.*]] to <8 x i16>
+; CHECK-NEXT:    [[R:%.*]] = shufflevector <8 x i16> [[X0]], <8 x i16> [[X1]], <16 x i32> <i32 1, i32 0, i32 3, i32 3, i32 5, i32 4, i32 7, i32 6, i32 9, i32 8, i32 11, i32 10, i32 13, i32 12, i32 15, i32 14>
+; CHECK-NEXT:    ret <16 x i16> [[R]]
 ;
-  %x0 = bitcast <4 x i32> %a0 to <4 x float>
-  %x1 = bitcast <4 x i32> %a1 to <4 x float>
-  %r = shufflevector <4 x float> %x0, <4 x float> %x1, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7>
-  ret <8 x float> %r
+  %x0 = bitcast <4 x i32> %a0 to <8 x i16>
+  %x1 = bitcast <4 x i32> %a1 to <8 x i16>
+  %r = shufflevector <8 x i16> %x0, <8 x i16> %x1, <16 x i32> <i32 1, i32 0, i32 3, i32 3, i32 5, i32 4, i32 7, i32 6, i32 9, i32 8, i32 11, i32 10, i32 13, i32 12, i32 15, i32 14>
+  ret <16 x i16> %r
 }
 
 ; negative - src type mismatch