Commit Graph

12 Commits

Author SHA1 Message Date
Juergen Ributzka 4bf6c01cdb Reapply [FastISel] Let the target decide first if it wants to materialize a constant (215588).
Note: This was originally reverted to track down a buildbot error. This commit
exposed a latent bug that was fixed in r215753. Therefore it is reapplied
without any modifications.

I run it through SPEC2k and SPEC2k6 for AArch64 and it didn't introduce any new
regeressions.

Original commit message:
This changes the order in which FastISel tries to materialize a constant.
Originally it would try to use a simple target-independent approach, which
can lead to the generation of inefficient code.

On X86 this would result in the use of movabsq to materialize any 64bit
integer constant - even for simple and small values such as 0 and 1. Also
some very funny floating-point materialization could be observed too.

On AArch64 it would materialize the constant 0 in a register even the
architecture has an actual "zero" register.

On ARM it would generate unnecessary mov instructions or not use mvn.

This change simply changes the order and always asks the target first if it
likes to materialize the constant. This doesn't fix all the issues
mentioned above, but it enables the targets to implement such
optimizations.

Related to <rdar://problem/17420988>.

llvm-svn: 216006
2014-08-19 19:05:24 +00:00
Juergen Ributzka a6faae3c11 [FastISel][ARM] Fix unit test from r215682.
Thanks Jim for finding this.

llvm-svn: 215733
2014-08-15 17:23:20 +00:00
Juergen Ributzka 81db58e177 [FastISel][ARM] Fall-back to constant pool loads when materializing an i32 constant.
FastEmit_i won't always succeed to materialize an i32 constant and just fail.
This would trigger a fall-back to SelectionDAG, which is really not necessary.

This fix will first fall-back to a constant pool load to materialize the constant
before giving up for good.

This fixes <rdar://problem/18022633>.

llvm-svn: 215682
2014-08-14 23:29:49 +00:00
Juergen Ributzka 790bacf232 Revert several FastISel commits to track down a buildbot error.
This reverts:
r215595 "[FastISel][X86] Add large code model support for materializing floating-point constants."
r215594 "[FastISel][X86] Use XOR to materialize the "0" value."
r215593 "[FastISel][X86] Emit more efficient instructions for integer constant materialization."
r215591 "[FastISel][AArch64] Make use of the zero register when possible."
r215588 "[FastISel] Let the target decide first if it wants to materialize a constant."
r215582 "[FastISel][AArch64] Cleanup constant materialization code. NFCI."

llvm-svn: 215673
2014-08-14 19:56:28 +00:00
Juergen Ributzka 7cee768e55 [FastISel] Let the target decide first if it wants to materialize a constant.
This changes the order in which FastISel tries to materialize a constant.
Originally it would try to use a simple target-independent approach, which
can lead to the generation of inefficient code.

On X86 this would result in the use of movabsq to materialize any 64bit
integer constant - even for simple and small values such as 0 and 1. Also
some very funny floating-point materialization could be observed too.

On AArch64 it would materialize the constant 0 in a register even the
architecture has an actual "zero" register.

On ARM it would generate unnecessary mov instructions or not use mvn.

This change simply changes the order and always asks the target first if it
likes to materialize the constant. This doesn't fix all the issues
mentioned above, but it enables the targets to implement such
optimizations.

Related to <rdar://problem/17420988>.

llvm-svn: 215588
2014-08-13 22:08:02 +00:00
Juergen Ributzka a5b083853c [FastISel][ARM] Use MOVT/MOVW if the subtarget requests it.
This change is also in preparation for a future change to make sure that
the constant materialization uses MOVT/MOVW when available and not a load
from the constant pool.

llvm-svn: 215584
2014-08-13 21:42:19 +00:00
JF Bastien 18db1f2f1a Enable FastISel on ARM for Linux and NaCl, not MCJIT
This is a resubmit of r182877, which was reverted because it broken
MCJIT tests on ARM. The patch leaves MCJIT on ARM as it was before: only
enabled for iOS. I've CC'ed people from the original review and revert.

FastISel was only enabled for iOS ARM and Thumb2, this patch enables it
for ARM (not Thumb2) on Linux and NaCl, but not MCJIT.

Thumb2 support needs a bit more work, mainly around register class
restrictions.

The patch punts to SelectionDAG when doing TLS relocation on non-Darwin
targets. I will fix this and other FastISel-to-SelectionDAG failures in
a separate patch.

The patch also forces FastISel to retain frame pointers: iOS always
keeps them for backtracking (so emitted code won't change because of
this), but Linux was getting much worse code that was incorrect when
using big frames (such as test-suite's lencod). I'll also fix this in a
later patch, it will probably require a peephole so that FastISel
doesn't rematerialize frame pointers back-to-back.

The test changes are straightforward, similar to:
  http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130513/174279.html
They also add a vararg test that got dropped in that change.

I ran all of lnt test-suite on A15 hardware with --optimize-option=-O0
and all the tests pass. All the tests also pass on x86 make check-all. I
also re-ran the check-all tests that failed on ARM, and they all seem to
pass.

llvm-svn: 183966
2013-06-14 02:49:43 +00:00
Rafael Espindola 99bd2ae479 Revert r182937 and r182877.
r182877 broke MCJIT tests on ARM and r182937 was working around another failure
by r182877.

This should make the ARM bots green.

llvm-svn: 182960
2013-05-30 20:37:52 +00:00
JF Bastien f60e0e44ca Enable FastISel on ARM for Linux and NaCl
FastISel was only enabled for iOS ARM and Thumb2, this patch enables it
for ARM (not Thumb2) on Linux and NaCl.

Thumb2 support needs a bit more work, mainly around register class
restrictions.

The patch punts to SelectionDAG when doing TLS relocation on non-Darwin
targets. I will fix this and other FastISel-to-SelectionDAG failures in
a separate patch.

The patch also forces FastISel to retain frame pointers: iOS always
keeps them for backtracking (so emitted code won't change because of
this), but Linux was getting much worse code that was incorrect when
using big frames (such as test-suite's lencod). I'll also fix this in a
later patch, it will probably require a peephole so that FastISel
doesn't rematerialize frame pointers back-to-back.

The test changes are straightforward, similar to:
  http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130513/174279.html
They also add a vararg test that got dropped in that change.

I ran all of test-suite on A15 hardware with --optimize-option=-O0 and
all the tests pass.

llvm-svn: 182877
2013-05-29 20:38:10 +00:00
Derek Schuff bd7c6e5015 Fix ARM FastISel tests, as a first step to enabling ARM FastISel
ARM FastISel is currently only enabled for iOS non-Thumb1, and I'm working on
enabling it for other targets. As a first step I've fixed some of the tests.
Changes to ARM FastISel tests:
- Different triples don't generate the same relocations (especially
  movw/movt versus constant pool loads). Use a regex to allow either.
- Mangling is different. Use a regex to allow either.
- The reserved registers are sometimes different, so registers get
  allocated in a different order. Capture the names only where this
  occurs.
- Add -verify-machineinstrs to some tests where it works. It doesn't
  work everywhere it should yet.
- Add -fast-isel-abort to many tests that didn't have it before.
- Split out the VarArg test from fast-isel-call.ll into its own
  test. This simplifies test setup because of --check-prefix.

Patch by JF Bastien

llvm-svn: 181801
2013-05-14 16:26:38 +00:00
Evan Cheng 68132d8093 ARM target code clean up. Check for iOS, not Darwin where it makes sense.
llvm-svn: 146981
2011-12-20 18:26:50 +00:00
Chad Rosier 2a3503e061 Add support for using MVN to materialize negative constants.
rdar://10412592

llvm-svn: 144348
2011-11-11 00:36:21 +00:00