Reapply [FastISel][AArch64] Make use of the zero register when possible (r215591).

Note: This was originally reverted to track down a buildbot error. Reapply
without any modifications.

Original commit message:
This change materializes now the value "0" from the zero register.
The zero register can be folded by several instruction, so no
materialization is need at all.

Fixes <rdar://problem/17924413>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216009 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Juergen Ributzka 2014-08-19 19:44:02 +00:00
parent 7d84c8ec54
commit 78f686d37c
5 changed files with 59 additions and 16 deletions

View File

@ -217,7 +217,19 @@ unsigned AArch64FastISel::TargetMaterializeAlloca(const AllocaInst *AI) {
unsigned AArch64FastISel::AArch64MaterializeInt(const ConstantInt *CI, MVT VT) {
if (VT > MVT::i64)
return 0;
return FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
if (!CI->isZero())
return FastEmit_i(VT, VT, ISD::Constant, CI->getZExtValue());
// Create a copy from the zero register to materialize a "0" value.
const TargetRegisterClass *RC = (VT == MVT::i64) ? &AArch64::GPR64RegClass
: &AArch64::GPR32RegClass;
unsigned ZeroReg = (VT == MVT::i64) ? AArch64::XZR : AArch64::WZR;
unsigned ResultReg = createResultReg(RC);
BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
TII.get(TargetOpcode::COPY), ResultReg)
.addReg(ZeroReg, getKillRegState(true));
return ResultReg;
}
unsigned AArch64FastISel::AArch64MaterializeFP(const ConstantFP *CFP, MVT VT) {

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@ -42,7 +42,7 @@ entry:
define i32 @sext_(i8 %a, i16 %b) nounwind {
entry:
; CHECK-LABEL: @sext_
; CHECK-LABEL: sext_
; CHECK: sxtb w0, w0
; CHECK: sxth w1, w1
; CHECK: bl _foo_sext_
@ -54,7 +54,7 @@ declare void @foo_sext_(i8 %a, i16 %b)
define i32 @zext_(i8 %a, i16 %b) nounwind {
entry:
; CHECK-LABEL: @zext_
; CHECK-LABEL: zext_
; CHECK: uxtb w0, w0
; CHECK: uxth w1, w1
call void @foo_zext_(i8 zeroext %a, i16 zeroext %b)
@ -78,17 +78,18 @@ declare i32 @bar(i8 zeroext, i8 zeroext, i8 zeroext, i8 zeroext, i8 zeroext, i8
; Test materialization of integers. Target-independent selector handles this.
define i32 @t2() {
entry:
; CHECK-LABEL: @t2
; CHECK: movz x0, #0
; CHECK-LABEL: t2
; CHECK: mov [[REG1:x[0-9]+]], xzr
; CHECK: orr w1, wzr, #0xfffffff8
; CHECK: orr w[[REG:[0-9]+]], wzr, #0x3ff
; CHECK: orr w[[REG2:[0-9]+]], wzr, #0x2
; CHECK: movz w[[REG3:[0-9]+]], #0
; CHECK: orr w[[REG4:[0-9]+]], wzr, #0x1
; CHECK: uxth w2, w[[REG]]
; CHECK: sxtb w3, w[[REG2]]
; CHECK: and w4, w[[REG3]], #0x1
; CHECK: and w5, w[[REG4]], #0x1
; CHECK: orr [[REG2:w[0-9]+]], wzr, #0x3ff
; CHECK: orr [[REG3:w[0-9]+]], wzr, #0x2
; CHECK: mov [[REG4:w[0-9]+]], wzr
; CHECK: orr [[REG5:w[0-9]+]], wzr, #0x1
; CHECK: mov x0, [[REG1]]
; CHECK: uxth w2, [[REG2]]
; CHECK: sxtb w3, [[REG3]]
; CHECK: and w4, [[REG4]], #0x1
; CHECK: and w5, [[REG5]], #0x1
; CHECK: bl _func2
%call = call i32 @func2(i64 zeroext 0, i32 signext -8, i16 zeroext 1023, i8 signext -254, i1 zeroext 0, i1 zeroext 1)
ret i32 0

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@ -7,7 +7,7 @@ define void @t1() {
; ARM64-LABEL: t1
; ARM64: adrp x8, _message@PAGE
; ARM64: add x0, x8, _message@PAGEOFF
; ARM64: movz w9, #0
; ARM64: mov w9, wzr
; ARM64: movz x2, #0x50
; ARM64: uxtb w1, w9
; ARM64: bl _memset

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@ -0,0 +1,30 @@
; RUN: llc -mtriple=aarch64-unknown-unknown < %s | FileCheck %s
; RUN: llc -mtriple=aarch64-unknown-unknown -fast-isel -fast-isel-abort < %s | FileCheck %s
define void @store_i8(i8* %a) {
; CHECK-LABEL: store_i8
; CHECK: strb wzr, [x0]
store i8 0, i8* %a
ret void
}
define void @store_i16(i16* %a) {
; CHECK-LABEL: store_i16
; CHECK: strh wzr, [x0]
store i16 0, i16* %a
ret void
}
define void @store_i32(i32* %a) {
; CHECK-LABEL: store_i32
; CHECK: str wzr, [x0]
store i32 0, i32* %a
ret void
}
define void @store_i64(i64* %a) {
; CHECK-LABEL: store_i64
; CHECK: str xzr, [x0]
store i64 0, i64* %a
ret void
}

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@ -66,7 +66,7 @@ entry:
define void @t4(i32 *%ptr) nounwind {
entry:
; CHECK-LABEL: t4:
; CHECK: movz w8, #0
; CHECK: mov w8, wzr
; CHECK: stur w8, [x0, #-4]
; CHECK: ret
%0 = getelementptr i32 *%ptr, i32 -1
@ -77,7 +77,7 @@ entry:
define void @t5(i32 *%ptr) nounwind {
entry:
; CHECK-LABEL: t5:
; CHECK: movz w8, #0
; CHECK: mov w8, wzr
; CHECK: stur w8, [x0, #-256]
; CHECK: ret
%0 = getelementptr i32 *%ptr, i32 -64