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[X86] Prefer rotate by 1 over rotate by imm

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Summary:
Rotate by 1 is translated to 1 micro-op, while rotate with imm8 is translated to 2 micro-ops.

Fixes pr30644.

Reviewers: delena, igorb, craig.topper, spatel, RKSimon

Differential Revision: https://reviews.llvm.org/D25399

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283758 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Zvi Rackover 2016-10-10 14:43:55 +00:00
parent 5ba17d7d92
commit bca70faf12
2 changed files with 11 additions and 11 deletions
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8
lib/Target/X86/X86InstrShiftRotate.td
View File

@ -609,19 +609,19 @@ def ROR64ri : RIi8<0xC1, MRM1r, (outs GR64:$dst),
// Rotate by 1
def ROR8r1 : I<0xD0, MRM1r, (outs GR8 :$dst), (ins GR8 :$src1),
"ror{b}\t$dst",
[(set GR8:$dst, (rotr GR8:$src1, (i8 1)))],
[(set GR8:$dst, (rotl GR8:$src1, (i8 7)))],
IIC_SR>;
def ROR16r1 : I<0xD1, MRM1r, (outs GR16:$dst), (ins GR16:$src1),
"ror{w}\t$dst",
[(set GR16:$dst, (rotr GR16:$src1, (i8 1)))],
[(set GR16:$dst, (rotl GR16:$src1, (i8 15)))],
IIC_SR>, OpSize16;
def ROR32r1 : I<0xD1, MRM1r, (outs GR32:$dst), (ins GR32:$src1),
"ror{l}\t$dst",
[(set GR32:$dst, (rotr GR32:$src1, (i8 1)))],
[(set GR32:$dst, (rotl GR32:$src1, (i8 31)))],
IIC_SR>, OpSize32;
def ROR64r1 : RI<0xD1, MRM1r, (outs GR64:$dst), (ins GR64:$src1),
"ror{q}\t$dst",
[(set GR64:$dst, (rotr GR64:$src1, (i8 1)))],
[(set GR64:$dst, (rotl GR64:$src1, (i8 63)))],
IIC_SR>;
} // Constraints = "$src = $dst", SchedRW

14
test/CodeGen/X86/rotate.ll
View File

@ -183,7 +183,7 @@ define i64 @rotr1_64(i64 %A) nounwind {
;
; 64-LABEL: rotr1_64:
; 64: # BB#0:
; 64-NEXT: rolq $63, %rdi
; 64-NEXT: rorq %rdi
; 64-NEXT: movq %rdi, %rax
; 64-NEXT: retq
%B = shl i64 %A, 63
@ -296,12 +296,12 @@ define i32 @rotr1_32(i32 %A) nounwind {
; 32-LABEL: rotr1_32:
; 32: # BB#0:
; 32-NEXT: movl {{[0-9]+}}(%esp), %eax
; 32-NEXT: roll $31, %eax
; 32-NEXT: rorl %eax
; 32-NEXT: retl
;
; 64-LABEL: rotr1_32:
; 64: # BB#0:
; 64-NEXT: roll $31, %edi
; 64-NEXT: rorl %edi
; 64-NEXT: movl %edi, %eax
; 64-NEXT: retq
%B = shl i32 %A, 31
@ -414,12 +414,12 @@ define i16 @rotr1_16(i16 %A) nounwind {
; 32-LABEL: rotr1_16:
; 32: # BB#0:
; 32-NEXT: movzwl {{[0-9]+}}(%esp), %eax
; 32-NEXT: rolw $15, %ax
; 32-NEXT: rorw %ax
; 32-NEXT: retl
;
; 64-LABEL: rotr1_16:
; 64: # BB#0:
; 64-NEXT: rolw $15, %di
; 64-NEXT: rorw %di
; 64-NEXT: movl %edi, %eax
; 64-NEXT: retq
%B = lshr i16 %A, 1
@ -528,12 +528,12 @@ define i8 @rotr1_8(i8 %A) nounwind {
; 32-LABEL: rotr1_8:
; 32: # BB#0:
; 32-NEXT: movb {{[0-9]+}}(%esp), %al
; 32-NEXT: rolb $7, %al
; 32-NEXT: rorb %al
; 32-NEXT: retl
;
; 64-LABEL: rotr1_8:
; 64: # BB#0:
; 64-NEXT: rolb $7, %dil
; 64-NEXT: rorb %dil
; 64-NEXT: movl %edi, %eax
; 64-NEXT: retq
%B = lshr i8 %A, 1