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[ARM] Mark LEApcrel instructions as isAsCheapAsAMove 

Doing this means that if an LEApcrel is used in two places we will rematerialize
instead of generating two MOVs. This is particularly useful for printfs using
the same format string, where we want to generate an address into a register
that's going to get corrupted by the call.

Differential Revision: https://reviews.llvm.org/D32858

llvm-svn: 303054
This commit is contained in:
John Brawn 2017-05-15 11:57:54 +00:00
parent 43132c46a6
commit 9486becf09
5 changed files with 33 additions and 4 deletions
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2
llvm/lib/Target/ARM/ARMInstrInfo.td
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@ -2222,7 +2222,7 @@ def ADR : AI1<{0,?,?,0}, (outs GPR:$Rd), (ins adrlabel:$label),
let Inst{11-0} = label{11-0};
}
let hasSideEffects = 0, isReMaterializable = 1 in
let hasSideEffects = 0, isReMaterializable = 1, isAsCheapAsAMove = 1 in
def LEApcrel : ARMPseudoInst<(outs GPR:$Rd), (ins i32imm:$label, pred:$p),
4, IIC_iALUi, []>, Sched<[WriteALU, ReadALU]>;

2
llvm/lib/Target/ARM/ARMInstrThumb.td
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@ -1402,7 +1402,7 @@ def tADR : T1I<(outs tGPR:$Rd), (ins t_adrlabel:$addr, pred:$p),
let DecoderMethod = "DecodeThumbAddSpecialReg";
}
let hasSideEffects = 0, isReMaterializable = 1 in
let hasSideEffects = 0, isReMaterializable = 1, isAsCheapAsAMove = 1 in
def tLEApcrel : tPseudoInst<(outs tGPR:$Rd), (ins i32imm:$label, pred:$p),
2, IIC_iALUi, []>, Sched<[WriteALU]>;

2
llvm/lib/Target/ARM/ARMInstrThumb2.td
View File

@ -1227,7 +1227,7 @@ def t2ADR : T2PCOneRegImm<(outs rGPR:$Rd),
let DecoderMethod = "DecodeT2Adr";
}
let hasSideEffects = 0, isReMaterializable = 1 in
let hasSideEffects = 0, isReMaterializable = 1, isAsCheapAsAMove = 1 in
def t2LEApcrel : t2PseudoInst<(outs rGPR:$Rd), (ins i32imm:$label, pred:$p),
4, IIC_iALUi, []>, Sched<[WriteALU, ReadALU]>;
let hasSideEffects = 1 in

25
llvm/test/CodeGen/ARM/adr-remat.ll Normal file
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@ -0,0 +1,25 @@
; RUN: llc -mtriple=armv7a %s -o - | FileCheck %s
; RUN: llc -mtriple=thumbv7m %s -o - | FileCheck %s
; RUN: llc -mtriple=thumbv6m %s -o - | FileCheck %s
@str.1 = private unnamed_addr constant [58 x i8] c"+-------------------------------------------------------+\00"
@str.2 = private unnamed_addr constant [58 x i8] c"| |\00"
declare i32 @puts(i8* nocapture readonly)
; Check that we rematerialize the adr of str.1 instead of doing one adr and two
; movs.
; CHECK: adr r0, [[STR1:.LCPI[0-9]+_[0-9]+]]
; CHECK: bl puts
; CHECK: adr r0, {{.LCPI[0-9]+_[0-9]+}}
; CHECK: bl puts
; CHECK: adr r0, [[STR1]]
; CHECK: b{{l?}} puts
define void @fn() {
entry:
%puts1 = tail call i32 @puts(i8* getelementptr inbounds ([58 x i8], [58 x i8]* @str.1, i32 0, i32 0))
%puts2 = tail call i32 @puts(i8* getelementptr inbounds ([58 x i8], [58 x i8]* @str.2, i32 0, i32 0))
%puts3 = tail call i32 @puts(i8* getelementptr inbounds ([58 x i8], [58 x i8]* @str.1, i32 0, i32 0))
ret void
}

6
llvm/test/CodeGen/ARM/align-sp-adjustment.ll
View File

@ -1,6 +1,10 @@
; RUN: llc -mtriple=thumbv7 -o - %s | FileCheck %s
; CHECK: [sp, #2120]
; p5 will have been pushed to the stack. Check that it's correctly aligned by
; looking at the offset of the instruction that loads it. Note that this is
; very fragile and this test may need to be updated if we happen to spill more
; or less to the stack.
; CHECK: ldr{{(.w)?}} r{{[0-9]+}}, [sp, #2104]
%struct.struct_2 = type { [172 x %struct.struct_1] }
%struct.struct_1 = type { i32, i32, i32 }