From 5effb5c6a161c1bdbdd9585dfdc97a6105e3df66 Mon Sep 17 00:00:00 2001
From: rdivacky <rdivacky@FreeBSD.org>
Date: Thu, 15 Oct 2009 07:47:49 +0000
Subject: Update llvm to r84175.
---
lib/Target/ARM/ARMConstantIslandPass.cpp | 33 +++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)
(limited to 'lib/Target/ARM/ARMConstantIslandPass.cpp')
diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 309e3ba..b0bd04b 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -74,16 +74,28 @@ namespace {
/// CPUser - One user of a constant pool, keeping the machine instruction
/// pointer, the constant pool being referenced, and the max displacement
- /// allowed from the instruction to the CP.
+ /// allowed from the instruction to the CP. The HighWaterMark records the
+ /// highest basic block where a new CPEntry can be placed. To ensure this
+ /// pass terminates, the CP entries are initially placed at the end of the
+ /// function and then move monotonically to lower addresses. The
+ /// exception to this rule is when the current CP entry for a particular
+ /// CPUser is out of range, but there is another CP entry for the same
+ /// constant value in range. We want to use the existing in-range CP
+ /// entry, but if it later moves out of range, the search for new water
+ /// should resume where it left off. The HighWaterMark is used to record
+ /// that point.
struct CPUser {
MachineInstr *MI;
MachineInstr *CPEMI;
+ MachineBasicBlock *HighWaterMark;
unsigned MaxDisp;
bool NegOk;
bool IsSoImm;
CPUser(MachineInstr *mi, MachineInstr *cpemi, unsigned maxdisp,
bool neg, bool soimm)
- : MI(mi), CPEMI(cpemi), MaxDisp(maxdisp), NegOk(neg), IsSoImm(soimm) {}
+ : MI(mi), CPEMI(cpemi), MaxDisp(maxdisp), NegOk(neg), IsSoImm(soimm) {
+ HighWaterMark = CPEMI->getParent();
+ }
};
/// CPUsers - Keep track of all of the machine instructions that use various
@@ -962,8 +974,8 @@ bool ARMConstantIslands::LookForWater(CPUser &U, unsigned UserOffset,
B = WaterList.begin();; --IP) {
MachineBasicBlock* WaterBB = *IP;
// Check if water is in range and at a lower address than the current one.
- if (WaterIsInRange(UserOffset, WaterBB, U) &&
- WaterBB->getNumber() < U.CPEMI->getParent()->getNumber()) {
+ if (WaterBB->getNumber() < U.HighWaterMark->getNumber() &&
+ WaterIsInRange(UserOffset, WaterBB, U)) {
unsigned WBBId = WaterBB->getNumber();
if (isThumb &&
(BBOffsets[WBBId] + BBSizes[WBBId])%4 != 0) {
@@ -1006,14 +1018,12 @@ void ARMConstantIslands::CreateNewWater(unsigned CPUserIndex,
BBSizes[UserMBB->getNumber()];
assert(OffsetOfNextBlock== BBOffsets[UserMBB->getNumber()+1]);
- // If the use is at the end of the block, or the end of the block
- // is within range, make new water there. (The addition below is
- // for the unconditional branch we will be adding: 4 bytes on ARM + Thumb2,
- // 2 on Thumb1. Possible Thumb1 alignment padding is allowed for
+ // If the block does not end in an unconditional branch already, and if the
+ // end of the block is within range, make new water there. (The addition
+ // below is for the unconditional branch we will be adding: 4 bytes on ARM +
+ // Thumb2, 2 on Thumb1. Possible Thumb1 alignment padding is allowed for
// inside OffsetIsInRange.
- // If the block ends in an unconditional branch already, it is water,
- // and is known to be out of range, so we'll always be adding a branch.)
- if (&UserMBB->back() == UserMI ||
+ if (BBHasFallthrough(UserMBB) &&
OffsetIsInRange(UserOffset, OffsetOfNextBlock + (isThumb1 ? 2: 4),
U.MaxDisp, U.NegOk, U.IsSoImm)) {
DEBUG(errs() << "Split at end of block\n");
@@ -1131,6 +1141,7 @@ bool ARMConstantIslands::HandleConstantPoolUser(MachineFunction &MF,
// Now that we have an island to add the CPE to, clone the original CPE and
// add it to the island.
+ U.HighWaterMark = NewIsland;
U.CPEMI = BuildMI(NewIsland, DebugLoc::getUnknownLoc(),
TII->get(ARM::CONSTPOOL_ENTRY))
.addImm(ID).addConstantPoolIndex(CPI).addImm(Size);
--
cgit v1.1