From a5fec0dba34206274041543b5924d2565fb10f9b Mon Sep 17 00:00:00 2001 From: Duncan Sands Date: Tue, 17 Mar 2009 09:46:22 +0000 Subject: [PATCH] Reapply r67049, with the test adjusted for darwin (which produces "call L_f$stub" rather than "call f"). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67079 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/PHIElimination.cpp | 100 ++++++++++++++++----------- test/CodeGen/X86/2009-03-13-PHIElimBug.ll | 55 ++++++--------- test/CodeGen/X86/2009-03-16-PHIElimInLPad.ll | 21 ++++++ 3 files changed, 105 insertions(+), 71 deletions(-) create mode 100644 test/CodeGen/X86/2009-03-16-PHIElimInLPad.ll diff --git a/lib/CodeGen/PHIElimination.cpp b/lib/CodeGen/PHIElimination.cpp index 6f3c82c7081..67c555fd17f 100644 --- a/lib/CodeGen/PHIElimination.cpp +++ b/lib/CodeGen/PHIElimination.cpp @@ -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 BBVRegPair; typedef std::map 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; - - // Trying to walk pass the EH try range. If we run into a use instruction, - // we want to insert the copy there. - SmallPtrSet 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); +// 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(); + + // 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(MBB.getBasicBlock()->getTerminator())) + return MBB.getFirstTerminator(); + + // Discover any definition/uses in this basic block. + SmallPtrSet 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); diff --git a/test/CodeGen/X86/2009-03-13-PHIElimBug.ll b/test/CodeGen/X86/2009-03-13-PHIElimBug.ll index ea4150c22c2..b01556de482 100644 --- a/test/CodeGen/X86/2009-03-13-PHIElimBug.ll +++ b/test/CodeGen/X86/2009-03-13-PHIElimBug.ll @@ -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() { -entry: - %0 = invoke i8* @__gnat_malloc(i32 12) - to label %invcont unwind label %lpad ; [#uses=0] - -invcont: ; preds = %entry - %1 = invoke i8* @__gnat_malloc(i32 20) - to label %invcont1 unwind label %lpad ; [#uses=0] - -invcont1: ; preds = %invcont - %2 = invoke i32 @report__ident_int(i32 2) - to label %.noexc unwind label %lpad ; [#uses=0] - -.noexc: ; preds = %invcont1 - %3 = invoke i32 @report__ident_int(i32 3) - to label %.noexc88 unwind label %lpad ; [#uses=0] +declare i32 @g() -.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 ; [#uses=1] - %5 = load i32* %4, align 4 ; [#uses=0] - ret void +define i32 @phi() { +entry: + %a = call i32 @f() ; [#uses=1] + %b = invoke i32 @g() + to label %cont unwind label %lpad ; [#uses=1] + +cont: ; preds = %entry + %x = phi i32 [ %b, %entry ] ; [#uses=0] + %aa = call i32 @g() ; [#uses=1] + %bb = invoke i32 @g() + to label %cont2 unwind label %lpad ; [#uses=1] + +cont2: ; preds = %cont + %xx = phi i32 [ %bb, %cont ] ; [#uses=1] + ret i32 %xx + +lpad: ; preds = %cont, %entry + %y = phi i32 [ %a, %entry ], [ %aa, %cont ] ; [#uses=1] + ret i32 %y } - -declare i32 @report__ident_int(i32) - -declare i8* @__gnat_malloc(i32) diff --git a/test/CodeGen/X86/2009-03-16-PHIElimInLPad.ll b/test/CodeGen/X86/2009-03-16-PHIElimInLPad.ll new file mode 100644 index 00000000000..c079ae73725 --- /dev/null +++ b/test/CodeGen/X86/2009-03-16-PHIElimInLPad.ll @@ -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 ; [#uses=1] + +cont: ; preds = %entry + %b = invoke i32 @f() + to label %cont2 unwind label %lpad ; [#uses=1] + +cont2: ; preds = %cont + ret i32 %b + +lpad: ; preds = %cont, %entry + %v = phi i32 [ %x, %entry ], [ %a, %cont ] ; [#uses=1] + ret i32 %v +} -- 2.11.0