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[AArch64] Run a peephole pass right after AdvSIMD pass. 

The AdvSIMD pass may produce copies that are not coalescer-friendly. The
peephole optimizer knows how to fix that as demonstrated in the test case.

<rdar://problem/12702965>

llvm-svn: 216200
This commit is contained in:
Quentin Colombet 2014-08-21 18:10:07 +00:00
parent c83265a6c5
commit 0c740d4b9a
2 changed files with 28 additions and 3 deletions
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6
llvm/lib/Target/AArch64/AArch64TargetMachine.cpp
View File

@ -195,8 +195,12 @@ bool AArch64PassConfig::addILPOpts() {
bool AArch64PassConfig::addPreRegAlloc() { bool AArch64PassConfig::addPreRegAlloc() {
// Use AdvSIMD scalar instructions whenever profitable. // Use AdvSIMD scalar instructions whenever profitable.
if (TM->getOptLevel() != CodeGenOpt::None && EnableAdvSIMDScalar) if (TM->getOptLevel() != CodeGenOpt::None && EnableAdvSIMDScalar) {
addPass(createAArch64AdvSIMDScalar()); addPass(createAArch64AdvSIMDScalar());
// The AdvSIMD pass may produce copies that can be rewritten to
// be register coaleascer friendly.
addPass(&PeepholeOptimizerID);
}
return true; return true;
} }

25
llvm/test/CodeGen/AArch64/arm64-AdvSIMD-Scalar.ll
View File

@ -1,15 +1,36 @@
; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=apple -aarch64-simd-scalar=true -asm-verbose=false | FileCheck %s ; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=apple -aarch64-simd-scalar=true -asm-verbose=false -disable-adv-copy-opt=true | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-NOOPT
; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=generic -aarch64-simd-scalar=true -asm-verbose=false | FileCheck %s -check-prefix=GENERIC ; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=apple -aarch64-simd-scalar=true -asm-verbose=false -disable-adv-copy-opt=false | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-OPT
; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=generic -aarch64-simd-scalar=true -asm-verbose=false -disable-adv-copy-opt=true | FileCheck %s -check-prefix=GENERIC -check-prefix=GENERIC-NOOPT
; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=generic -aarch64-simd-scalar=true -asm-verbose=false -disable-adv-copy-opt=false | FileCheck %s -check-prefix=GENERIC -check-prefix=GENERIC-OPT
define <2 x i64> @bar(<2 x i64> %a, <2 x i64> %b) nounwind readnone { define <2 x i64> @bar(<2 x i64> %a, <2 x i64> %b) nounwind readnone {
; CHECK-LABEL: bar: ; CHECK-LABEL: bar:
; CHECK: add.2d v[[REG:[0-9]+]], v0, v1 ; CHECK: add.2d v[[REG:[0-9]+]], v0, v1
; CHECK: add d[[REG3:[0-9]+]], d[[REG]], d1 ; CHECK: add d[[REG3:[0-9]+]], d[[REG]], d1
; Without advanced copy optimization, we end up with cross register
; banks copies that cannot be coalesced.
; CHECK-NOOPT: fmov [[COPY_REG3:x[0-9]+]], d[[REG3]]
; With advanced copy optimization, we end up with just one copy
; to insert the computed high part into the V register.
; CHECK-OPT-NOT: fmov
; CHECK: sub d[[REG2:[0-9]+]], d[[REG]], d1 ; CHECK: sub d[[REG2:[0-9]+]], d[[REG]], d1
; CHECK: fmov [[COPY_REG2:x[0-9]+]], d[[REG2]]
; CHECK-NOOPT: fmov d0, [[COPY_REG3]]
; CHECK-OPT-NOT: fmov
; CHECK: ins.d v0[1], [[COPY_REG2]]
; CHECK-NEXT: ret
;
; GENERIC-LABEL: bar: ; GENERIC-LABEL: bar:
; GENERIC: add v[[REG:[0-9]+]].2d, v0.2d, v1.2d ; GENERIC: add v[[REG:[0-9]+]].2d, v0.2d, v1.2d
; GENERIC: add d[[REG3:[0-9]+]], d[[REG]], d1 ; GENERIC: add d[[REG3:[0-9]+]], d[[REG]], d1
; GENERIC-NOOPT: fmov [[COPY_REG3:x[0-9]+]], d[[REG3]]
; GENERIC-OPT-NOT: fmov
; GENERIC: sub d[[REG2:[0-9]+]], d[[REG]], d1 ; GENERIC: sub d[[REG2:[0-9]+]], d[[REG]], d1
; GENERIC: fmov [[COPY_REG2:x[0-9]+]], d[[REG2]]
; GENERIC-NOOPT: fmov d0, [[COPY_REG3]]
; GENERIC-OPT-NOT: fmov
; GENERIC: ins v0.d[1], [[COPY_REG2]]
; GENERIC-NEXT: ret
%add = add <2 x i64> %a, %b %add = add <2 x i64> %a, %b
%vgetq_lane = extractelement <2 x i64> %add, i32 0 %vgetq_lane = extractelement <2 x i64> %add, i32 0
%vgetq_lane2 = extractelement <2 x i64> %b, i32 0 %vgetq_lane2 = extractelement <2 x i64> %b, i32 0