[InstCombine] canonicalize another raw IR rotate pattern to funnel shift

This is matching the equivalent of the DAG expansion, 
so it should never end up with worse perf than the 
original code even if the target doesn't have a rotate
instruction.

llvm-svn: 350672

1 files changed, 5 insertions, 28 deletions

diff --git a/llvm/test/Transforms/InstCombine/rotate.ll b/llvm/test/Transforms/InstCombine/rotate.ll
index cc6735fe393..4b516003a9f 100644
--- a/llvm/test/Transforms/InstCombine/rotate.ll
+++ b/llvm/test/Transforms/InstCombine/rotate.ll
@@ -213,12 +213,7 @@ define <3 x i42> @rotr_v3i42(<3 x i42> %x, <3 x i42> %y) {
 
 define i32 @rotl_safe_i32(i32 %x, i32 %y) {
 ; CHECK-LABEL: @rotl_safe_i32(
-; CHECK-NEXT:    [[NEGY:%.*]] = sub i32 0, [[Y:%.*]]
-; CHECK-NEXT:    [[YMASK:%.*]] = and i32 [[Y]], 31
-; CHECK-NEXT:    [[NEGYMASK:%.*]] = and i32 [[NEGY]], 31
-; CHECK-NEXT:    [[SHL:%.*]] = shl i32 [[X:%.*]], [[YMASK]]
-; CHECK-NEXT:    [[SHR:%.*]] = lshr i32 [[X]], [[NEGYMASK]]
-; CHECK-NEXT:    [[R:%.*]] = or i32 [[SHR]], [[SHL]]
+; CHECK-NEXT:    [[R:%.*]] = call i32 @llvm.fshl.i32(i32 [[X:%.*]], i32 [[X]], i32 [[Y:%.*]])
 ; CHECK-NEXT:    ret i32 [[R]]
 ;
   %negy = sub i32 0, %y
@@ -236,12 +231,9 @@ define i32 @rotl_safe_i32(i32 %x, i32 %y) {
 define i16 @rotl_safe_i16_commute_extra_use(i16 %x, i16 %y, i16* %p) {
 ; CHECK-LABEL: @rotl_safe_i16_commute_extra_use(
 ; CHECK-NEXT:    [[NEGY:%.*]] = sub i16 0, [[Y:%.*]]
-; CHECK-NEXT:    [[YMASK:%.*]] = and i16 [[Y]], 15
 ; CHECK-NEXT:    [[NEGYMASK:%.*]] = and i16 [[NEGY]], 15
 ; CHECK-NEXT:    store i16 [[NEGYMASK]], i16* [[P:%.*]], align 2
-; CHECK-NEXT:    [[SHL:%.*]] = shl i16 [[X:%.*]], [[YMASK]]
-; CHECK-NEXT:    [[SHR:%.*]] = lshr i16 [[X]], [[NEGYMASK]]
-; CHECK-NEXT:    [[R:%.*]] = or i16 [[SHL]], [[SHR]]
+; CHECK-NEXT:    [[R:%.*]] = call i16 @llvm.fshl.i16(i16 [[X:%.*]], i16 [[X]], i16 [[Y]])
 ; CHECK-NEXT:    ret i16 [[R]]
 ;
   %negy = sub i16 0, %y
@@ -259,12 +251,7 @@ define i16 @rotl_safe_i16_commute_extra_use(i16 %x, i16 %y, i16* %p) {
 
 define i64 @rotr_safe_i64(i64 %x, i64 %y) {
 ; CHECK-LABEL: @rotr_safe_i64(
-; CHECK-NEXT:    [[NEGY:%.*]] = sub i64 0, [[Y:%.*]]
-; CHECK-NEXT:    [[YMASK:%.*]] = and i64 [[Y]], 63
-; CHECK-NEXT:    [[NEGYMASK:%.*]] = and i64 [[NEGY]], 63
-; CHECK-NEXT:    [[SHL:%.*]] = shl i64 [[X:%.*]], [[NEGYMASK]]
-; CHECK-NEXT:    [[SHR:%.*]] = lshr i64 [[X]], [[YMASK]]
-; CHECK-NEXT:    [[R:%.*]] = or i64 [[SHR]], [[SHL]]
+; CHECK-NEXT:    [[R:%.*]] = call i64 @llvm.fshr.i64(i64 [[X:%.*]], i64 [[X]], i64 [[Y:%.*]])
 ; CHECK-NEXT:    ret i64 [[R]]
 ;
   %negy = sub i64 0, %y
@@ -305,12 +292,7 @@ define i8 @rotr_safe_i8_commute_extra_use(i8 %x, i8 %y, i8* %p) {
 
 define <2 x i32> @rotl_safe_v2i32(<2 x i32> %x, <2 x i32> %y) {
 ; CHECK-LABEL: @rotl_safe_v2i32(
-; CHECK-NEXT:    [[NEGY:%.*]] = sub <2 x i32> zeroinitializer, [[Y:%.*]]
-; CHECK-NEXT:    [[YMASK:%.*]] = and <2 x i32> [[Y]], <i32 31, i32 31>
-; CHECK-NEXT:    [[NEGYMASK:%.*]] = and <2 x i32> [[NEGY]], <i32 31, i32 31>
-; CHECK-NEXT:    [[SHL:%.*]] = shl <2 x i32> [[X:%.*]], [[YMASK]]
-; CHECK-NEXT:    [[SHR:%.*]] = lshr <2 x i32> [[X]], [[NEGYMASK]]
-; CHECK-NEXT:    [[R:%.*]] = or <2 x i32> [[SHR]], [[SHL]]
+; CHECK-NEXT:    [[R:%.*]] = call <2 x i32> @llvm.fshl.v2i32(<2 x i32> [[X:%.*]], <2 x i32> [[X]], <2 x i32> [[Y:%.*]])
 ; CHECK-NEXT:    ret <2 x i32> [[R]]
 ;
   %negy = sub <2 x i32> zeroinitializer, %y
@@ -327,12 +309,7 @@ define <2 x i32> @rotl_safe_v2i32(<2 x i32> %x, <2 x i32> %y) {
 
 define <3 x i16> @rotr_safe_v3i16(<3 x i16> %x, <3 x i16> %y) {
 ; CHECK-LABEL: @rotr_safe_v3i16(
-; CHECK-NEXT:    [[NEGY:%.*]] = sub <3 x i16> zeroinitializer, [[Y:%.*]]
-; CHECK-NEXT:    [[YMASK:%.*]] = and <3 x i16> [[Y]], <i16 15, i16 15, i16 15>
-; CHECK-NEXT:    [[NEGYMASK:%.*]] = and <3 x i16> [[NEGY]], <i16 15, i16 15, i16 15>
-; CHECK-NEXT:    [[SHL:%.*]] = shl <3 x i16> [[X:%.*]], [[NEGYMASK]]
-; CHECK-NEXT:    [[SHR:%.*]] = lshr <3 x i16> [[X]], [[YMASK]]
-; CHECK-NEXT:    [[R:%.*]] = or <3 x i16> [[SHR]], [[SHL]]
+; CHECK-NEXT:    [[R:%.*]] = call <3 x i16> @llvm.fshr.v3i16(<3 x i16> [[X:%.*]], <3 x i16> [[X]], <3 x i16> [[Y:%.*]])
 ; CHECK-NEXT:    ret <3 x i16> [[R]]
 ;
   %negy = sub <3 x i16> zeroinitializer, %y