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[Sparc] Check register use with isPhysRegUsed() instead of reg_nodbg_empty() 

Summary: By using reg_nodbg_empty() to determine if a function can be
treated as a leaf function or not, we miss the case when the register
pair L0_L1 is used but not L0 by itself. This has the effect that
use_all_i32_regs(), a test in reserved-regs.ll which tries to use all
registers, gets treated as a leaf function.

Reviewers: jyknight, venkatra

Reviewed By: jyknight

Subscribers: davide, RKSimon, sepavloff, llvm-commits

Differential Revision: https://reviews.llvm.org/D27089

llvm-svn: 297285
This commit is contained in:
Daniel Cederman 2017-03-08 15:23:10 +00:00
parent ac170872b2
commit 9db582a656
2 changed files with 8 additions and 7 deletions
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11
llvm/lib/Target/Sparc/SparcFrameLowering.cpp
View File

@ -288,11 +288,11 @@ static bool LLVM_ATTRIBUTE_UNUSED verifyLeafProcRegUse(MachineRegisterInfo *MRI)
{
for (unsigned reg = SP::I0; reg <= SP::I7; ++reg)
if (!MRI->reg_nodbg_empty(reg))
if (MRI->isPhysRegUsed(reg))
return false;
for (unsigned reg = SP::L0; reg <= SP::L7; ++reg)
if (!MRI->reg_nodbg_empty(reg))
if (MRI->isPhysRegUsed(reg))
return false;
return true;
@ -305,8 +305,8 @@ bool SparcFrameLowering::isLeafProc(MachineFunction &MF) const
MachineFrameInfo &MFI = MF.getFrameInfo();
return !(MFI.hasCalls() // has calls
|| !MRI.reg_nodbg_empty(SP::L0) // Too many registers needed
|| !MRI.reg_nodbg_empty(SP::O6) // %SP is used
|| MRI.isPhysRegUsed(SP::L0) // Too many registers needed
|| MRI.isPhysRegUsed(SP::O6) // %SP is used
|| hasFP(MF)); // need %FP
}
@ -314,11 +314,10 @@ void SparcFrameLowering::remapRegsForLeafProc(MachineFunction &MF) const {
MachineRegisterInfo &MRI = MF.getRegInfo();
// Remap %i[0-7] to %o[0-7].
for (unsigned reg = SP::I0; reg <= SP::I7; ++reg) {
if (MRI.reg_nodbg_empty(reg))
if (!MRI.isPhysRegUsed(reg))
continue;
unsigned mapped_reg = reg - SP::I0 + SP::O0;
assert(MRI.reg_nodbg_empty(mapped_reg));
// Replace I register with O register.
MRI.replaceRegWith(reg, mapped_reg);

4
llvm/test/CodeGen/SPARC/reserved-regs.ll
View File

@ -1,4 +1,4 @@
; RUN: llc -march=sparc < %s | FileCheck %s
; RUN: llc -march=sparc -verify-machineinstrs < %s | FileCheck %s
@g = common global [32 x i32] zeroinitializer, align 16
@h = common global [16 x i64] zeroinitializer, align 16
@ -6,6 +6,7 @@
;; Ensures that we don't use registers which are supposed to be reserved.
; CHECK-LABEL: use_all_i32_regs:
; CHECK: save %sp
; CHECK-NOT: %g0
; CHECK-NOT: %g1
; CHECK-NOT: %g5
@ -86,6 +87,7 @@ entry:
; CHECK-LABEL: use_all_i64_regs:
; CHECK: save %sp
; CHECK-NOT: %g0
; CHECK-NOT: %g1
; CHECK-NOT: %g4