[llvm] r325573 - [ARM] Mark -1 as cheap in xor's for thumb1
David Green via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 20 03:07:35 PST 2018
Author: dmgreen
Date: Tue Feb 20 03:07:35 2018
New Revision: 325573
URL: http://llvm.org/viewvc/llvm-project?rev=325573&view=rev
Log:
[ARM] Mark -1 as cheap in xor's for thumb1
We can always convert xor %a, -1 into MVN, even in thumb 1 where the -1
would not otherwise be considered a cheap constant. This prevents the
-1's from being pulled out into constants and potentially hoisted.
Differential Revision: https://reviews.llvm.org/D43451
Added:
llvm/trunk/test/CodeGen/Thumb/mvn.ll
Modified:
llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
Modified: llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp?rev=325573&r1=325572&r2=325573&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMTargetTransformInfo.cpp Tue Feb 20 03:07:35 2018
@@ -126,6 +126,13 @@ int ARMTTIImpl::getIntImmCost(unsigned O
return 0;
}
+ // xor a, -1 can always be folded to MVN
+ if (Opcode == Instruction::Xor) {
+ int64_t NegImm = Imm.getSExtValue();
+ if (NegImm == -1)
+ return 0;
+ }
+
return getIntImmCost(Imm, Ty);
}
Added: llvm/trunk/test/CodeGen/Thumb/mvn.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Thumb/mvn.ll?rev=325573&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Thumb/mvn.ll (added)
+++ llvm/trunk/test/CodeGen/Thumb/mvn.ll Tue Feb 20 03:07:35 2018
@@ -0,0 +1,193 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=thumbv6m-eabi -asm-verbose=false %s -o - | FileCheck %s
+
+define void @test8(i8* %a) {
+; CHECK-LABEL: test8:
+; CHECK: ldrb r1, [r0]
+; CHECK-NEXT: mvns r1, r1
+; CHECK-NEXT: strb r1, [r0]
+; CHECK-NEXT: bx lr
+ %x = load i8, i8* %a
+ %xn = xor i8 %x, -1
+ store i8 %xn, i8* %a
+ ret void
+}
+
+define void @test8_2(i8* %a, i8* %b) {
+; CHECK-LABEL: test8_2:
+; CHECK: ldrb r2, [r1]
+; CHECK-NEXT: ldrb r3, [r0]
+; CHECK-NEXT: mvns r3, r3
+; CHECK-NEXT: strb r3, [r0]
+; CHECK-NEXT: mvns r0, r2
+; CHECK-NEXT: strb r0, [r1]
+; CHECK-NEXT: bx lr
+ %x = load i8, i8* %a
+ %y = load i8, i8* %b
+ %xn = xor i8 %x, -1
+ %yn = xor i8 %y, -1
+ store i8 %xn, i8* %a
+ store i8 %yn, i8* %b
+ ret void
+}
+
+define void @loop8(i8* %a) {
+; CHECK-LABEL: loop8:
+; CHECK: movs r1, #0
+; CHECK-NEXT: .LBB2_1:
+; CHECK-NEXT: ldrb r2, [r0, r1]
+; CHECK-NEXT: mvns r2, r2
+; CHECK-NEXT: strb r2, [r0, r1]
+; CHECK-NEXT: adds r1, r1, #1
+; CHECK-NEXT: cmp r1, #10
+; CHECK-NEXT: bne .LBB2_1
+; CHECK-NEXT: bx lr
+entry:
+ br label %for.body
+
+for.body:
+ %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+ %arrayidx = getelementptr inbounds i8, i8* %a, i32 %i
+ %x = load i8, i8* %arrayidx
+ %xn = xor i8 %x, -1
+ store i8 %xn, i8* %arrayidx
+ %inc = add nuw nsw i32 %i, 1
+ %exitcond = icmp eq i32 %inc, 10
+ br i1 %exitcond, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+ ret void
+}
+
+define void @loop8_2(i8* %a, i8* %b) {
+; CHECK-LABEL: loop8_2:
+; CHECK: .save {r4, lr}
+; CHECK-NEXT: push {r4, lr}
+; CHECK-NEXT: movs r2, #0
+; CHECK-NEXT: .LBB3_1:
+; CHECK-NEXT: ldrb r3, [r1, r2]
+; CHECK-NEXT: ldrb r4, [r0, r2]
+; CHECK-NEXT: mvns r4, r4
+; CHECK-NEXT: strb r4, [r0, r2]
+; CHECK-NEXT: mvns r3, r3
+; CHECK-NEXT: strb r3, [r1, r2]
+; CHECK-NEXT: adds r2, r2, #1
+; CHECK-NEXT: cmp r2, #10
+; CHECK-NEXT: bne .LBB3_1
+; CHECK-NEXT: pop {r4, pc}
+entry:
+ br label %for.body
+
+for.body:
+ %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+ %arrayidx = getelementptr inbounds i8, i8* %a, i32 %i
+ %arrayidx2 = getelementptr inbounds i8, i8* %b, i32 %i
+ %x = load i8, i8* %arrayidx
+ %y = load i8, i8* %arrayidx2
+ %xn = xor i8 %x, -1
+ %yn = xor i8 %y, -1
+ store i8 %xn, i8* %arrayidx
+ store i8 %yn, i8* %arrayidx2
+ %inc = add nuw nsw i32 %i, 1
+ %exitcond = icmp eq i32 %inc, 10
+ br i1 %exitcond, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+ ret void
+}
+
+define void @test32(i32* %a) {
+; CHECK-LABEL: test32:
+; CHECK: ldr r1, [r0]
+; CHECK-NEXT: mvns r1, r1
+; CHECK-NEXT: str r1, [r0]
+; CHECK-NEXT: bx lr
+ %x = load i32, i32* %a
+ %xn = xor i32 %x, -1
+ store i32 %xn, i32* %a
+ ret void
+}
+
+define void @test32_2(i32* %a, i32* %b) {
+; CHECK-LABEL: test32_2:
+; CHECK: ldr r2, [r1]
+; CHECK-NEXT: ldr r3, [r0]
+; CHECK-NEXT: mvns r3, r3
+; CHECK-NEXT: str r3, [r0]
+; CHECK-NEXT: mvns r0, r2
+; CHECK-NEXT: str r0, [r1]
+; CHECK-NEXT: bx lr
+ %x = load i32, i32* %a
+ %y = load i32, i32* %b
+ %xn = xor i32 %x, -1
+ %yn = xor i32 %y, -1
+ store i32 %xn, i32* %a
+ store i32 %yn, i32* %b
+ ret void
+}
+
+define void @loop32(i32* %a) {
+; CHECK-LABEL: loop32:
+; CHECK: movs r1, #0
+; CHECK-NEXT: .LBB6_1:
+; CHECK-NEXT: ldr r2, [r0, r1]
+; CHECK-NEXT: mvns r2, r2
+; CHECK-NEXT: str r2, [r0, r1]
+; CHECK-NEXT: adds r1, r1, #4
+; CHECK-NEXT: cmp r1, #40
+; CHECK-NEXT: bne .LBB6_1
+; CHECK-NEXT: bx lr
+entry:
+ br label %for.body
+
+for.body:
+ %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+ %arrayidx = getelementptr inbounds i32, i32* %a, i32 %i
+ %x = load i32, i32* %arrayidx
+ %xn = xor i32 %x, -1
+ store i32 %xn, i32* %arrayidx
+ %inc = add nuw nsw i32 %i, 1
+ %exitcond = icmp eq i32 %inc, 10
+ br i1 %exitcond, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+ ret void
+}
+
+define void @loop32_2(i32* %a, i32* %b) {
+; CHECK-LABEL: loop32_2:
+; CHECK: .save {r4, lr}
+; CHECK-NEXT: push {r4, lr}
+; CHECK-NEXT: movs r2, #0
+; CHECK-NEXT: .LBB7_1:
+; CHECK-NEXT: ldr r3, [r1, r2]
+; CHECK-NEXT: ldr r4, [r0, r2]
+; CHECK-NEXT: mvns r4, r4
+; CHECK-NEXT: str r4, [r0, r2]
+; CHECK-NEXT: mvns r3, r3
+; CHECK-NEXT: str r3, [r1, r2]
+; CHECK-NEXT: adds r2, r2, #4
+; CHECK-NEXT: cmp r2, #40
+; CHECK-NEXT: bne .LBB7_1
+; CHECK-NEXT: pop {r4, pc}
+entry:
+ br label %for.body
+
+for.body:
+ %i = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+ %arrayidx = getelementptr inbounds i32, i32* %a, i32 %i
+ %arrayidx2 = getelementptr inbounds i32, i32* %b, i32 %i
+ %x = load i32, i32* %arrayidx
+ %y = load i32, i32* %arrayidx2
+ %xn = xor i32 %x, -1
+ %yn = xor i32 %y, -1
+ store i32 %xn, i32* %arrayidx
+ store i32 %yn, i32* %arrayidx2
+ %inc = add nuw nsw i32 %i, 1
+ %exitcond = icmp eq i32 %inc, 10
+ br i1 %exitcond, label %for.cond.cleanup, label %for.body
+
+for.cond.cleanup:
+ ret void
+}
+
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