llvm-svn: 130028

Sometimes it is better to split per block, and we missed those cases.

llvm-svn: 130025

fix bugs exposed by the gcc dejagnu testsuite:
1. The load may actually be used by a dead instruction, which
   would cause an assert.
2. The load may not be used by the current chain of instructions,
   and we could move it past a side-effecting instruction. Change
   how we process uses to define the problem away.

llvm-svn: 130018

print out ldr, not ldr.n.

rdar://problem/9267772

llvm-svn: 130008

On x86 this allows to fold a load into the cmp, greatly reducing register pressure.
  movzbl	(%rdi), %eax
  cmpl	$47, %eax
->
  cmpb	$47, (%rdi)

This shaves 8k off gcc.o on i386. I'll leave applying the patch in README.txt to Chris :)

llvm-svn: 130005

llvm-svn: 130004

llvm-svn: 129995

X86: Try to use a smaller encoding by transforming (X << C1) & C2 into (X & (C2 >> C1)) & C1. (Part of PR5039)

This tends to happen a lot with bitfield code generated by clang. A simple example for x86_64 is
uint64_t foo(uint64_t x) { return (x&1) << 42; }
which used to compile into bloated code:
	shlq	$42, %rdi               ## encoding: [0x48,0xc1,0xe7,0x2a]
	movabsq	$4398046511104, %rax    ## encoding: [0x48,0xb8,0x00,0x00,0x00,0x00,0x00,0x04,0x00,0x00]
	andq	%rdi, %rax              ## encoding: [0x48,0x21,0xf8]
	ret                             ## encoding: [0xc3]

with this patch we can fold the immediate into the and:
	andq	$1, %rdi                ## encoding: [0x48,0x83,0xe7,0x01]
	movq	%rdi, %rax              ## encoding: [0x48,0x89,0xf8]
	shlq	$42, %rax               ## encoding: [0x48,0xc1,0xe0,0x2a]
	ret                             ## encoding: [0xc3]

It's possible to save another byte by using 'andl' instead of 'andq' but I currently see no way of doing
that without making this code even more complicated. See the TODOs in the code.

llvm-svn: 129990

llvm-svn: 129984

llvm-svn: 129980

llvm-svn: 129978

llvm-svn: 129976

llvm-svn: 129975

Patch by Patrick Walton!

llvm-svn: 129974

llvm-svn: 129973

add <rd>, sp, #<imm8>
ldr <rd>, [sp, #<imm8>]
When the offset from sp is multiple of 4 and in range of 0-1020.
This saves code size by utilizing 16-bit instructions.

rdar://9321541

llvm-svn: 129971

llvm-svn: 129970

the first time through.

llvm-svn: 129969

Silences GCC warning.

I wonder why Clang doesn't warn on this...

llvm-svn: 129968

An exception is thrown via a call to _cxa_throw, which we don't expect to
return. Therefore, the "true" part of the invoke goes to a BB that has
'unreachable' as its only instruction. This is lowered into an empty MachineBB.
The landing pad for this invoke, however, is directly after the "true" MBB.
When the empty MBB is removed, the landing pad is directly below the BB with the
invoke call. The unconditional branch is removed and then the two blocks are
merged together.

The testcase is too big for a regression test.
<rdar://problem/9305728>

llvm-svn: 129965

X8664_ELFTargetObjectFile::getFDEEncoding to match reality.

llvm-svn: 129959

llvm-svn: 129955

llvm-svn: 129953

llvm-svn: 129952

llvm-svn: 129947

llvm-svn: 129945

llvm-svn: 129938

llvm-svn: 129932

llvm-svn: 129928

These intervals are allocatable immediately after splitting, but they may be
evicted because of later splitting. This is rare, but when it happens they
should be split again.

The remainder intervals that cannot be allocated after splitting still move
directly to spilling.

SplitEditor::finish can optionally provide a mapping from new live intervals
back to the original interval indexes returned by openIntv().

Each original interval index can map to multiple new intervals after connected
components have been separated. Dead code elimination may also add existing
intervals to the list.

The reverse mapping allows the SplitEditor client to treat the new intervals
differently depending on the split region they came from.

llvm-svn: 129925

MC :-)

llvm-svn: 129923

llvm-svn: 129922

llvm-svn: 129921

which broke a couple GCC test suite tests at -O0.

llvm-svn: 129914

llvm-svn: 129913

This patch depends on the prior fix r129908 that changes to use std::find,
rather than std::binary_search, on unordered array.

Patch by Dan Bailey

llvm-svn: 129909

llvm-svn: 129908

necessary since gcov counts transitions between blocks. It can't see if you've
run every line in a straight-line function, so we add an edge for it to notice.

llvm-svn: 129905

comment for 80 columns.

llvm-svn: 129904

instrument the program to emit .gcda.
TODO: we should emit slightly different .gcda files when .gcno emission is off.

llvm-svn: 129903