[PATCH] D64986: [IPRA][ARM] Make use of the "returned" parameter attribute
Oliver Stannard (Linaro) via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 22 01:51:50 PDT 2019
This revision was automatically updated to reflect the committed changes.
Closed by commit rL366669: [IPRA][ARM] Make use of the "returned" parameter attribute (authored by ostannard, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D64986?vs=210797&id=211028#toc
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D64986/new/
https://reviews.llvm.org/D64986
Files:
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
llvm/trunk/lib/Target/ARM/ARMMachineFunctionInfo.h
llvm/trunk/test/CodeGen/ARM/ipra-r0-returned.ll
Index: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -9615,6 +9615,8 @@
Flags.setOrigAlign(OriginalAlignment);
if (ArgCopyElisionCandidates.count(&Arg))
Flags.setCopyElisionCandidate();
+ if (Arg.hasAttribute(Attribute::Returned))
+ Flags.setReturned();
MVT RegisterVT = TLI->getRegisterTypeForCallingConv(
*CurDAG->getContext(), F.getCallingConv(), VT);
Index: llvm/trunk/lib/Target/ARM/ARMMachineFunctionInfo.h
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMMachineFunctionInfo.h
+++ llvm/trunk/lib/Target/ARM/ARMMachineFunctionInfo.h
@@ -130,6 +130,10 @@
/// The amount the literal pool has been increasedby due to promoted globals.
int PromotedGlobalsIncrease = 0;
+ /// True if r0 will be preserved by a call to this function (e.g. C++
+ /// con/destructors).
+ bool PreservesR0 = false;
+
public:
ARMFunctionInfo() = default;
@@ -247,6 +251,9 @@
}
DenseMap<unsigned, unsigned> EHPrologueRemappedRegs;
+
+ void setPreservesR0() { PreservesR0 = true; }
+ bool getPreservesR0() const { return PreservesR0; }
};
} // end namespace llvm
Index: llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
+++ llvm/trunk/lib/Target/ARM/ARMFrameLowering.cpp
@@ -2097,6 +2097,12 @@
AFI->setLRIsSpilledForFarJump(true);
}
AFI->setLRIsSpilled(SavedRegs.test(ARM::LR));
+
+ // If we have the "returned" parameter attribute which guarantees that we
+ // return the value which was passed in r0 unmodified (e.g. C++ 'structors),
+ // record that fact for IPRA.
+ if (AFI->getPreservesR0())
+ SavedRegs.set(ARM::R0);
}
MachineBasicBlock::iterator ARMFrameLowering::eliminateCallFramePseudoInstr(
Index: llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
+++ llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
@@ -3898,6 +3898,12 @@
// Transform the arguments in physical registers into virtual ones.
unsigned Reg = MF.addLiveIn(VA.getLocReg(), RC);
ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, RegVT);
+
+ // If this value is passed in r0 and has the returned attribute (e.g.
+ // C++ 'structors), record this fact for later use.
+ if (VA.getLocReg() == ARM::R0 && Ins[VA.getValNo()].Flags.isReturned()) {
+ AFI->setPreservesR0();
+ }
}
// If this is an 8 or 16-bit value, it is really passed promoted
Index: llvm/trunk/test/CodeGen/ARM/ipra-r0-returned.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/ipra-r0-returned.ll
+++ llvm/trunk/test/CodeGen/ARM/ipra-r0-returned.ll
@@ -0,0 +1,18 @@
+; RUN: llc -mtriple armv7a--none-eabi -enable-ipra=false < %s | FileCheck %s
+; RUN: llc -mtriple armv7a--none-eabi -enable-ipra=true < %s | FileCheck %s
+
+define i32 @returns_r0(i32 returned %a) {
+entry:
+ call void asm sideeffect "", "~{r0}"()
+ ret i32 %a
+}
+
+define i32 @test(i32 %a) {
+; CHECK-LABEL: test:
+entry:
+; CHECK-NOT: r0
+; CHECK: bl returns_r0
+; CHECK-NOT: r0
+ %b = call i32 @returns_r0(i32 %a)
+ ret i32 %a
+}
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D64986.211028.patch
Type: text/x-patch
Size: 3553 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190722/86c32f1b/attachment.bin>
More information about the llvm-commits
mailing list