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Reapply r67049, with the test adjusted for darwin 

(which produces "call L_f$stub" rather than "call f").

llvm-svn: 67079
This commit is contained in:
Duncan Sands 2009-03-17 09:46:22 +00:00
parent 523c0852c6
commit fb5c74ef4b
3 changed files with 101 additions and 67 deletions
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98
llvm/lib/CodeGen/PHIElimination.cpp
View File

@ -14,6 +14,8 @@
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "phielim"
#include "llvm/BasicBlock.h"
#include "llvm/Instructions.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
@ -31,7 +33,6 @@
using namespace llvm;
STATISTIC(NumAtomic, "Number of atomic phis lowered");
STATISTIC(NumEH, "Number of EH try blocks skipped");
namespace {
class VISIBILITY_HIDDEN PNE : public MachineFunctionPass {
@ -66,8 +67,25 @@ namespace {
///
void analyzePHINodes(const MachineFunction& Fn);
void WalkPassEHTryRange(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &I, unsigned SrcReg);
// FindCopyInsertPoint - Find a safe place in MBB to insert a copy from
// SrcReg. This needs to be after any def or uses of SrcReg, but before
// any subsequent point where control flow might jump out of the basic
// block.
MachineBasicBlock::iterator FindCopyInsertPoint(MachineBasicBlock &MBB,
unsigned SrcReg);
// SkipPHIsAndLabels - Copies need to be inserted after phi nodes and
// also after any exception handling labels: in landing pads execution
// starts at the label, so any copies placed before it won't be executed!
MachineBasicBlock::iterator SkipPHIsAndLabels(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I) {
// Rather than assuming that EH labels come before other kinds of labels,
// just skip all labels.
while (I != MBB.end() &&
(I->getOpcode() == TargetInstrInfo::PHI || I->isLabel()))
++I;
return I;
}
typedef std::pair<const MachineBasicBlock*, unsigned> BBVRegPair;
typedef std::map<BBVRegPair, unsigned> VRegPHIUse;
@ -120,10 +138,7 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) {
// Get an iterator to the first instruction after the last PHI node (this may
// also be the end of the basic block).
MachineBasicBlock::iterator AfterPHIsIt = MBB.begin();
while (AfterPHIsIt != MBB.end() &&
AfterPHIsIt->getOpcode() == TargetInstrInfo::PHI)
++AfterPHIsIt; // Skip over all of the PHI nodes...
MachineBasicBlock::iterator AfterPHIsIt = SkipPHIsAndLabels(MBB, MBB.begin());
while (MBB.front().getOpcode() == TargetInstrInfo::PHI)
LowerAtomicPHINode(MBB, AfterPHIsIt);
@ -144,37 +159,47 @@ static bool isSourceDefinedByImplicitDef(const MachineInstr *MPhi,
return true;
}
void PNE::WalkPassEHTryRange(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &I, unsigned SrcReg) {
if (I == MBB.begin())
return;
MachineBasicBlock::iterator PI = prior(I);
if (PI->getOpcode() != TargetInstrInfo::EH_LABEL)
return;
// FindCopyInsertPoint - Find a safe place in MBB to insert a copy from SrcReg.
// This needs to be after any def or uses of SrcReg, but before any subsequent
// point where control flow might jump out of the basic block.
MachineBasicBlock::iterator PNE::FindCopyInsertPoint(MachineBasicBlock &MBB,
unsigned SrcReg) {
// Handle the trivial case trivially.
if (MBB.empty())
return MBB.begin();
// Trying to walk pass the EH try range. If we run into a use instruction,
// we want to insert the copy there.
SmallPtrSet<MachineInstr*, 4> UsesInMBB;
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(SrcReg),
UE = MRI->use_end(); UI != UE; ++UI) {
MachineInstr *UseMI = &*UI;
if (UseMI->getParent() == &MBB)
UsesInMBB.insert(UseMI);
// If this basic block does not contain an invoke, then control flow always
// reaches the end of it, so place the copy there. The logic below works in
// this case too, but is more expensive.
if (!isa<InvokeInst>(MBB.getBasicBlock()->getTerminator()))
return MBB.getFirstTerminator();
// Discover any definition/uses in this basic block.
SmallPtrSet<MachineInstr*, 8> DefUsesInMBB;
for (MachineRegisterInfo::reg_iterator RI = MRI->reg_begin(SrcReg),
RE = MRI->reg_end(); RI != RE; ++RI) {
MachineInstr *DefUseMI = &*RI;
if (DefUseMI->getParent() == &MBB)
DefUsesInMBB.insert(DefUseMI);
}
while (PI != MBB.begin()) {
--PI;
if (PI->getOpcode() == TargetInstrInfo::EH_LABEL) {
++NumEH;
I = PI;
return;
} else if (UsesInMBB.count(&*PI)) {
++NumEH;
I = next(PI);
return;
}
MachineBasicBlock::iterator InsertPoint;
if (DefUsesInMBB.empty()) {
// No def/uses. Insert the copy at the start of the basic block.
InsertPoint = MBB.begin();
} else if (DefUsesInMBB.size() == 1) {
// Insert the copy immediately after the definition/use.
InsertPoint = *DefUsesInMBB.begin();
++InsertPoint;
} else {
// Insert the copy immediately after the last definition/use.
InsertPoint = MBB.end();
while (!DefUsesInMBB.count(&*--InsertPoint)) {}
++InsertPoint;
}
return;
// Make sure the copy goes after any phi nodes however.
return SkipPHIsAndLabels(MBB, InsertPoint);
}
/// LowerAtomicPHINode - Lower the PHI node at the top of the specified block,
@ -273,10 +298,7 @@ void PNE::LowerAtomicPHINode(MachineBasicBlock &MBB,
// Find a safe location to insert the copy, this may be the first terminator
// in the block (or end()).
MachineBasicBlock::iterator InsertPos = opBlock.getFirstTerminator();
// Walk pass EH try range if needed.
WalkPassEHTryRange(opBlock, InsertPos, SrcReg);
MachineBasicBlock::iterator InsertPos = FindCopyInsertPoint(opBlock, SrcReg);
// Insert the copy.
TII->copyRegToReg(opBlock, InsertPos, IncomingReg, SrcReg, RC, RC);

49
llvm/test/CodeGen/X86/2009-03-13-PHIElimBug.ll
View File

@ -1,37 +1,28 @@
; RUN: llvm-as < %s | llc -mtriple=i386-pc-linux-gnu -stats |& grep phielim | grep {Number of EH try blocks skipped} | grep 4
; RUN: llvm-as < %s | llc -march=x86 | grep -A 2 {call.*f} | grep movl
; Check the register copy comes after the call to f and before the call to g
; PR3784
%struct.c38002a__arr___XUB = type { i32, i32 }
%struct.c38002a__arr_name = type { [0 x i32]*, %struct.c38002a__arr___XUB* }
%struct.c38002a__rec = type { i32, %struct.c38002a__arr_name }
declare i32 @f()
define void @_ada_c38002a() {
declare i32 @g()
define i32 @phi() {
entry:
%0 = invoke i8* @__gnat_malloc(i32 12)
to label %invcont unwind label %lpad ; <i8*> [#uses=0]
%a = call i32 @f() ; <i32> [#uses=1]
%b = invoke i32 @g()
to label %cont unwind label %lpad ; <i32> [#uses=1]
invcont: ; preds = %entry
%1 = invoke i8* @__gnat_malloc(i32 20)
to label %invcont1 unwind label %lpad ; <i8*> [#uses=0]
cont: ; preds = %entry
%x = phi i32 [ %b, %entry ] ; <i32> [#uses=0]
%aa = call i32 @g() ; <i32> [#uses=1]
%bb = invoke i32 @g()
to label %cont2 unwind label %lpad ; <i32> [#uses=1]
invcont1: ; preds = %invcont
%2 = invoke i32 @report__ident_int(i32 2)
to label %.noexc unwind label %lpad ; <i32> [#uses=0]
cont2: ; preds = %cont
%xx = phi i32 [ %bb, %cont ] ; <i32> [#uses=1]
ret i32 %xx
.noexc: ; preds = %invcont1
%3 = invoke i32 @report__ident_int(i32 3)
to label %.noexc88 unwind label %lpad ; <i32> [#uses=0]
.noexc88: ; preds = %.noexc
unreachable
lpad: ; preds = %.noexc, %invcont1, %invcont, %entry
%r.0 = phi %struct.c38002a__rec* [ null, %entry ], [ null, %invcont ], [ null, %invcont1 ], [ null, %.noexc ] ; <%struct.c38002a__rec*> [#uses=1]
%4 = getelementptr %struct.c38002a__rec* %r.0, i32 0, i32 0 ; <i32*> [#uses=1]
%5 = load i32* %4, align 4 ; <i32> [#uses=0]
ret void
lpad: ; preds = %cont, %entry
%y = phi i32 [ %a, %entry ], [ %aa, %cont ] ; <i32> [#uses=1]
ret i32 %y
}
declare i32 @report__ident_int(i32)
declare i8* @__gnat_malloc(i32)

21
llvm/test/CodeGen/X86/2009-03-16-PHIElimInLPad.ll Normal file
View File

@ -0,0 +1,21 @@
; RUN: llvm-as < %s | llc -march=x86 | grep -A 1 lpad | grep Llabel
; Check that register copies in the landing pad come after the EH_LABEL
declare i32 @f()
define i32 @phi(i32 %x) {
entry:
%a = invoke i32 @f()
to label %cont unwind label %lpad ; <i32> [#uses=1]
cont: ; preds = %entry
%b = invoke i32 @f()
to label %cont2 unwind label %lpad ; <i32> [#uses=1]
cont2: ; preds = %cont
ret i32 %b
lpad: ; preds = %cont, %entry
%v = phi i32 [ %x, %entry ], [ %a, %cont ] ; <i32> [#uses=1]
ret i32 %v
}