InstSimplify: Add a hook for shufflevector
Summary:
Add a hook for simplification of shufflevector's with the following rules:
- Constant folding - NFC, as it was already being done by the default handler.
- If only one of the operands is constant, constant fold the shuffle if the
mask does not select elements from the variable operand - to show the hook is firing and affecting the test-cases.
Reviewers: RKSimon, craig.topper, spatel, sanjoy, nlopes, majnemer
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31525
llvm-svn: 299393
diff --git a/llvm/test/Transforms/InstSimplify/shufflevector.ll b/llvm/test/Transforms/InstSimplify/shufflevector.ll
index 4a9c0df..4b65801 100644
--- a/llvm/test/Transforms/InstSimplify/shufflevector.ll
+++ b/llvm/test/Transforms/InstSimplify/shufflevector.ll
@@ -3,13 +3,29 @@
define <4 x i32> @const_folding(<4 x i32> %x) {
; CHECK-LABEL: @const_folding(
-; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> zeroinitializer, <4 x i32> <i32 5, i32 4, i32 5, i32 4>
-; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+; CHECK-NEXT: ret <4 x i32> zeroinitializer
;
%shuf = shufflevector <4 x i32> %x, <4 x i32> zeroinitializer, <4 x i32> <i32 5, i32 4, i32 5, i32 4>
ret <4 x i32> %shuf
}
+define <4 x i32> @const_folding1(<4 x i32> %x) {
+; CHECK-LABEL: @const_folding1(
+; CHECK-NEXT: ret <4 x i32> <i32 5, i32 5, i32 5, i32 5>
+;
+ %shuf = shufflevector <4 x i32> <i32 5, i32 4, i32 5, i32 4>, <4 x i32> %x, <4 x i32> zeroinitializer
+ ret <4 x i32> %shuf
+}
+
+define <4 x i32> @const_folding_negative(<3 x i32> %x) {
+; CHECK-LABEL: @const_folding_negative(
+; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <3 x i32> [[X:%.*]], <3 x i32> zeroinitializer, <4 x i32> <i32 2, i32 4, i32 5, i32 4>
+; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+;
+ %shuf = shufflevector <3 x i32> %x, <3 x i32> zeroinitializer, <4 x i32> <i32 2, i32 4, i32 5, i32 4>
+ ret <4 x i32> %shuf
+}
+
define <4 x i32> @splat_operand(<4 x i32> %x) {
; CHECK-LABEL: @splat_operand(
; CHECK-NEXT: [[SPLAT:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> zeroinitializer
@@ -23,8 +39,7 @@
define <4 x i32> @undef_mask(<4 x i32> %x) {
; CHECK-LABEL: @undef_mask(
-; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> [[X:%.*]], <4 x i32> undef, <4 x i32> undef
-; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+; CHECK-NEXT: ret <4 x i32> undef
;
%shuf = shufflevector <4 x i32> %x, <4 x i32> undef, <4 x i32> undef
ret <4 x i32> %shuf
@@ -59,8 +74,7 @@
define <4 x i32> @const_operand(<4 x i32> %x) {
; CHECK-LABEL: @const_operand(
-; CHECK-NEXT: [[SHUF:%.*]] = shufflevector <4 x i32> <i32 42, i32 43, i32 44, i32 45>, <4 x i32> [[X:%.*]], <4 x i32> <i32 0, i32 3, i32 2, i32 1>
-; CHECK-NEXT: ret <4 x i32> [[SHUF]]
+; CHECK-NEXT: ret <4 x i32> <i32 42, i32 45, i32 44, i32 43>
;
%shuf = shufflevector <4 x i32> <i32 42, i32 43, i32 44, i32 45>, <4 x i32> %x, <4 x i32> <i32 0, i32 3, i32 2, i32 1>
ret <4 x i32> %shuf