[AArch64] Enable rematerialization of float 0 values.

Patch by Geoff Berry<gberry@codeaurora.org>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232967 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chad Rosier 2015-03-23 17:19:34 +00:00
parent a75fecc370
commit c1813d8fe1
2 changed files with 27 additions and 2 deletions

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@ -2348,8 +2348,15 @@ defm UCVTF : IntegerToFP<1, "ucvtf", uint_to_fp>;
defm FMOV : UnscaledConversion<"fmov">;
def : Pat<(f32 (fpimm0)), (FMOVWSr WZR)>, Requires<[NoZCZ]>;
def : Pat<(f64 (fpimm0)), (FMOVXDr XZR)>, Requires<[NoZCZ]>;
// Add pseudo ops for FMOV 0 so we can mark them as isReMaterializable
let isReMaterializable = 1, isCodeGenOnly = 1 in {
def FMOVS0 : Pseudo<(outs FPR32:$Rd), (ins), [(set f32:$Rd, (fpimm0))]>,
PseudoInstExpansion<(FMOVWSr FPR32:$Rd, WZR)>,
Requires<[NoZCZ]>;
def FMOVD0 : Pseudo<(outs FPR64:$Rd), (ins), [(set f64:$Rd, (fpimm0))]>,
PseudoInstExpansion<(FMOVXDr FPR64:$Rd, XZR)>,
Requires<[NoZCZ]>;
}
//===----------------------------------------------------------------------===//
// Floating point conversion instruction.

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@ -0,0 +1,18 @@
; RUN: llc < %s -mtriple=aarch64-none-linux-gnu -verify-machineinstrs
; Check that float 0 gets rematerialized with an fmov of zero reg instead
; of spilled/filled.
declare void @bar(float)
define void @foo() {
; CHECK-LABEL: foo:
; CHECK: fmov s0, wzr
; CHECK: bl bar
; CHECK: fmov s0, wzr
; CHECK: bl bar
call void @bar(float 0.000000e+00)
call void asm sideeffect "", "~{s0},~{s1},~{s2},~{s3},~{s4},~{s5},~{s6},~{s7},~{s8},~{s9},~{s10},~{s11},~{s12},~{s13},~{s14},~{s15},~{s16},~{s17},~{s18},~{s19},~{s20},~{s21},~{s22},~{s23},~{s24},~{s25},~{s26},~{s27},~{s28},~{s29},~{s30},~{s31}"()
call void @bar(float 0.000000e+00)
ret void
}