[ARM] Swap cmp operands for automatic shifts

Swap the compare operands if the lhs is a shift and the rhs isn't,
as in arm and T2 the shift can be performed by the compare for its
second operand.

Differential Revision: https://reviews.llvm.org/D39004

llvm-svn: 316562
This commit is contained in:
Sam Parker 2017-10-25 08:33:06 +00:00
parent 6ec2b8ac77
commit ccb209bb97
3 changed files with 160 additions and 52 deletions

View File

@ -3857,6 +3857,12 @@ SDValue ARMTargetLowering::getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
break;
}
}
} else if ((ARM_AM::getShiftOpcForNode(LHS.getOpcode()) != ARM_AM::no_shift) &&
(ARM_AM::getShiftOpcForNode(RHS.getOpcode()) == ARM_AM::no_shift)) {
// In ARM and Thumb-2, the compare instructions can shift their second
// operand.
CC = ISD::getSetCCSwappedOperands(CC);
std::swap(LHS, RHS);
}
ARMCC::CondCodes CondCode = IntCCToARMCC(CC);

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@ -0,0 +1,154 @@
; RUN: llc -mtriple=armv7 %s -o - | FileCheck %s
; RUN: llc -mtriple=thumb-eabi -mcpu=arm1156t2-s -mattr=+thumb2 %s -o - | FileCheck %s --check-prefix=CHECK-T2
define i1 @f1(i32 %a, i32 %b) {
; CHECK-LABEL: f1:
; CHECK: mov r2, #0
; CHECK: cmp r0, r1
; CHECK: movwne r2, #1
; CHECK: mov r0, r2
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp r0, r1
; CHECK-T2: movne r2, #1
; CHECK-T2: mov r0, r2
%tmp = icmp ne i32 %a, %b
ret i1 %tmp
}
define i1 @f2(i32 %a, i32 %b) {
; CHECK-LABEL: f2:
; CHECK: mov r2, #0
; CHECK: cmp r0, r1
; CHECK: movweq r2, #1
; CHECK: mov r0, r2
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp r0, r1
; CHECK-T2: moveq r2, #1
; CHECK-T2: mov r0, r2
%tmp = icmp eq i32 %a, %b
ret i1 %tmp
}
define i1 @f6(i32 %a, i32 %b) {
; CHECK-LABEL: f6:
; CHECK: mov r2, #0
; CHECK: cmp {{.*}}, r1, lsl #5
; CHECK: movweq r2, #1
; CHECK: mov r0, r2
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r0, r1, lsl #5
; CHECK-T2: moveq r2, #1
; CHECK-T2: mov r0, r2
%tmp = shl i32 %b, 5
%tmp1 = icmp eq i32 %a, %tmp
ret i1 %tmp1
}
define i1 @f7(i32 %a, i32 %b) {
; CHECK-LABEL: f7:
; CHECK: mov r2, #0
; CHECK: cmp r0, r1, lsr #6
; CHECK: movwne r2, #1
; CHECK: mov r0, r2
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r0, r1, lsr #6
; CHECK-T2: movne r2, #1
; CHECK-T2: mov r0, r2
%tmp = lshr i32 %b, 6
%tmp1 = icmp ne i32 %a, %tmp
ret i1 %tmp1
}
define i1 @f8(i32 %a, i32 %b) {
; CHECK-LABEL: f8:
; CHECK: mov r2, #0
; CHECK: cmp r0, r1, asr #7
; CHECK: movweq r2, #1
; CHECK: mov r0, r2
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r0, r1, asr #7
; CHECK-T2: moveq r2, #1
; CHECK-T2: mov r0, r2
%tmp = ashr i32 %b, 7
%tmp1 = icmp eq i32 %a, %tmp
ret i1 %tmp1
}
define i1 @f9(i32 %a) {
; CHECK-LABEL: f9:
; CHECK: mov r1, #0
; CHECK: cmp r0, r0, ror #8
; CHECK: movwne r1, #1
; CHECK: mov r0, r1
; CHECK-T2: mov{{.*}} r1, #0
; CHECK-T2: cmp.w r0, r0, ror #8
; CHECK-T2: movne r1, #1
; CHECK-T2: mov r0, r1
%l8 = shl i32 %a, 24
%r8 = lshr i32 %a, 8
%tmp = or i32 %l8, %r8
%tmp1 = icmp ne i32 %a, %tmp
ret i1 %tmp1
}
; CHECK-LABEL: swap_cmp_shl
; CHECK: mov r2, #0
; CHECK: cmp r1, r0, lsl #11
; CHECK: movwlt r2, #1
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r1, r0, lsl #11
; CHECK-T2: movlt r2, #1
define arm_aapcscc i32 @swap_cmp_shl(i32 %a, i32 %b) {
entry:
%shift = shl i32 %a, 11
%cmp = icmp sgt i32 %shift, %b
%conv = zext i1 %cmp to i32
ret i32 %conv
}
; CHECK-LABEL: swap_cmp_lshr
; CHECK: mov r2, #0
; CHECK: cmp r1, r0, lsr #11
; CHECK: movwhi r2, #1
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r1, r0, lsr #11
; CHECK-T2: movhi r2, #1
define arm_aapcscc i32 @swap_cmp_lshr(i32 %a, i32 %b) {
entry:
%shift = lshr i32 %a, 11
%cmp = icmp ult i32 %shift, %b
%conv = zext i1 %cmp to i32
ret i32 %conv
}
; CHECK-LABEL: swap_cmp_ashr
; CHECK: mov r2, #0
; CHECK: cmp r1, r0, asr #11
; CHECK: movwle r2, #1
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r1, r0, asr #11
; CHECK-T2: movle r2, #1
define arm_aapcscc i32 @swap_cmp_ashr(i32 %a, i32 %b) {
entry:
%shift = ashr i32 %a, 11
%cmp = icmp sge i32 %shift, %b
%conv = zext i1 %cmp to i32
ret i32 %conv
}
; CHECK-LABEL: swap_cmp_rotr
; CHECK: mov r2, #0
; CHECK: cmp r1, r0, ror #11
; CHECK: movwls r2, #1
; CHECK-T2: mov{{.*}} r2, #0
; CHECK-T2: cmp.w r1, r0, ror #11
; CHECK-T2: movls r2, #1
define arm_aapcscc i32 @swap_cmp_rotr(i32 %a, i32 %b) {
entry:
%lsr = lshr i32 %a, 11
%lsl = shl i32 %a, 21
%ror = or i32 %lsr, %lsl
%cmp = icmp uge i32 %ror, %b
%conv = zext i1 %cmp to i32
ret i32 %conv
}

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@ -1,52 +0,0 @@
; RUN: llc -mtriple=thumb-eabi -mcpu=arm1156t2-s -mattr=+thumb2 %s -o - | FileCheck %s
; These tests would be improved by 'movs r0, #0' being rematerialized below the
; test as 'mov.w r0, #0'.
define i1 @f1(i32 %a, i32 %b) {
; CHECK-LABEL: f1:
; CHECK: cmp {{.*}}, r1
%tmp = icmp ne i32 %a, %b
ret i1 %tmp
}
define i1 @f2(i32 %a, i32 %b) {
; CHECK-LABEL: f2:
; CHECK: cmp {{.*}}, r1
%tmp = icmp eq i32 %a, %b
ret i1 %tmp
}
define i1 @f6(i32 %a, i32 %b) {
; CHECK-LABEL: f6:
; CHECK: cmp.w {{.*}}, r1, lsl #5
%tmp = shl i32 %b, 5
%tmp1 = icmp eq i32 %tmp, %a
ret i1 %tmp1
}
define i1 @f7(i32 %a, i32 %b) {
; CHECK-LABEL: f7:
; CHECK: cmp.w {{.*}}, r1, lsr #6
%tmp = lshr i32 %b, 6
%tmp1 = icmp ne i32 %tmp, %a
ret i1 %tmp1
}
define i1 @f8(i32 %a, i32 %b) {
; CHECK-LABEL: f8:
; CHECK: cmp.w {{.*}}, r1, asr #7
%tmp = ashr i32 %b, 7
%tmp1 = icmp eq i32 %a, %tmp
ret i1 %tmp1
}
define i1 @f9(i32 %a, i32 %b) {
; CHECK-LABEL: f9:
; CHECK: cmp.w {{.*}}, {{.*}}, ror #8
%l8 = shl i32 %a, 24
%r8 = lshr i32 %a, 8
%tmp = or i32 %l8, %r8
%tmp1 = icmp ne i32 %a, %tmp
ret i1 %tmp1
}