[SelectionDAG] try to convert funnel shift directly to rotate if legal

If the DAGCombiner's rotate matching was working as expected, 
I don't think we'd see any test diffs here. 

This sidesteps the issue of custom lowering for rotates raised in PR38243:
https://bugs.llvm.org/show_bug.cgi?id=38243
...by only dealing with legal operations.

llvm-svn: 337966

3 files changed, 6 insertions, 12 deletions

diff --git a/llvm/test/CodeGen/AArch64/funnel-shift-rot.ll b/llvm/test/CodeGen/AArch64/funnel-shift-rot.ll
index 0b3bc665bdf..af612eafd33 100644
--- a/llvm/test/CodeGen/AArch64/funnel-shift-rot.ll
+++ b/llvm/test/CodeGen/AArch64/funnel-shift-rot.ll
@@ -163,11 +163,7 @@ define i32 @rotr_i32(i32 %x, i32 %z) {
 define i64 @rotr_i64(i64 %x, i64 %z) {
 ; CHECK-LABEL: rotr_i64:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    orr w9, wzr, #0x40
-; CHECK-NEXT:    sub w9, w9, w1
-; CHECK-NEXT:    lsr x8, x0, x1
-; CHECK-NEXT:    lsl x9, x0, x9
-; CHECK-NEXT:    orr x0, x9, x8
+; CHECK-NEXT:    ror x0, x0, x1
 ; CHECK-NEXT:    ret
   %f = call i64 @llvm.fshr.i64(i64 %x, i64 %x, i64 %z)
   ret i64 %f
diff --git a/llvm/test/CodeGen/PowerPC/funnel-shift-rot.ll b/llvm/test/CodeGen/PowerPC/funnel-shift-rot.ll
index b238504edc1..d93c9361b35 100644
--- a/llvm/test/CodeGen/PowerPC/funnel-shift-rot.ll
+++ b/llvm/test/CodeGen/PowerPC/funnel-shift-rot.ll
@@ -55,7 +55,6 @@ define i16 @rotl_i16(i16 %x, i16 %z) {
 define i32 @rotl_i32(i32 %x, i32 %z) {
 ; CHECK-LABEL: rotl_i32:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    rlwinm 4, 4, 0, 27, 31
 ; CHECK-NEXT:    rlwnm 3, 3, 4, 0, 31
 ; CHECK-NEXT:    blr
   %f = call i32 @llvm.fshl.i32(i32 %x, i32 %x, i32 %z)
@@ -65,8 +64,7 @@ define i32 @rotl_i32(i32 %x, i32 %z) {
 define i64 @rotl_i64(i64 %x, i64 %z) {
 ; CHECK-LABEL: rotl_i64:
 ; CHECK:       # %bb.0:
-; CHECK-NEXT:    rlwinm 4, 4, 0, 26, 31
-; CHECK-NEXT:    rotld 3, 3, 4
+; CHECK-NEXT:    rldcl 3, 3, 4, 0
 ; CHECK-NEXT:    blr
   %f = call i64 @llvm.fshl.i64(i64 %x, i64 %x, i64 %z)
   ret i64 %f
diff --git a/llvm/test/CodeGen/X86/funnel-shift-rot.ll b/llvm/test/CodeGen/X86/funnel-shift-rot.ll
index 2cdea080eea..edbdd8d9b92 100644
--- a/llvm/test/CodeGen/X86/funnel-shift-rot.ll
+++ b/llvm/test/CodeGen/X86/funnel-shift-rot.ll
@@ -169,12 +169,12 @@ define i8 @rotr_i8_const_shift(i8 %x) nounwind {
 ; X32-SSE2-LABEL: rotr_i8_const_shift:
 ; X32-SSE2:       # %bb.0:
 ; X32-SSE2-NEXT:    movb {{[0-9]+}}(%esp), %al
-; X32-SSE2-NEXT:    rolb $5, %al
+; X32-SSE2-NEXT:    rorb $3, %al
 ; X32-SSE2-NEXT:    retl
 ;
 ; X64-AVX2-LABEL: rotr_i8_const_shift:
 ; X64-AVX2:       # %bb.0:
-; X64-AVX2-NEXT:    rolb $5, %dil
+; X64-AVX2-NEXT:    rorb $3, %dil
 ; X64-AVX2-NEXT:    movl %edi, %eax
 ; X64-AVX2-NEXT:    retq
   %f = call i8 @llvm.fshr.i8(i8 %x, i8 %x, i8 3)
@@ -185,12 +185,12 @@ define i32 @rotr_i32_const_shift(i32 %x) nounwind {
 ; X32-SSE2-LABEL: rotr_i32_const_shift:
 ; X32-SSE2:       # %bb.0:
 ; X32-SSE2-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X32-SSE2-NEXT:    roll $29, %eax
+; X32-SSE2-NEXT:    rorl $3, %eax
 ; X32-SSE2-NEXT:    retl
 ;
 ; X64-AVX2-LABEL: rotr_i32_const_shift:
 ; X64-AVX2:       # %bb.0:
-; X64-AVX2-NEXT:    roll $29, %edi
+; X64-AVX2-NEXT:    rorl $3, %edi
 ; X64-AVX2-NEXT:    movl %edi, %eax
 ; X64-AVX2-NEXT:    retq
   %f = call i32 @llvm.fshr.i32(i32 %x, i32 %x, i32 3)