Commit Graph

8 Commits

Author SHA1 Message Date
Sanjoy Das b6c5914308 [InstCombine][CodeGenPrep] Create llvm.uadd.with.overflow in CGP.
Summary:
This change moves creating calls to `llvm.uadd.with.overflow` from
InstCombine to CodeGenPrep.  Combining overflow check patterns into
calls to the said intrinsic in InstCombine inhibits optimization because
it introduces an intrinsic call that not all other transforms and
analyses understand.

Depends on D8888.

Reviewers: majnemer, atrick

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8889

llvm-svn: 234638
2015-04-10 21:07:09 +00:00
Cameron McInally 44f3e30cf2 Revert r213070. It's breaking the build in MCELFStreamer::EmitInstToData(...).
llvm-svn: 213073
2014-07-15 16:24:24 +00:00
Cameron McInally 53bc7a3330 Add x86 patterns to match a specific add-with-carry.
llvm-svn: 213070
2014-07-15 15:03:32 +00:00
Stephen Lin f799e3f944 Convert CodeGen/*/*.ll tests to use the new CHECK-LABEL for easier debugging. No functionality change and all tests pass after conversion.
This was done with the following sed invocation to catch label lines demarking function boundaries:
    sed -i '' "s/^;\( *\)\([A-Z0-9_]*\):\( *\)test\([A-Za-z0-9_-]*\):\( *\)$/;\1\2-LABEL:\3test\4:\5/g" test/CodeGen/*/*.ll
which was written conservatively to avoid false positives rather than false negatives. I scanned through all the changes and everything looks correct.

llvm-svn: 186258
2013-07-13 20:38:47 +00:00
Shuxin Yang 01efdd6c28 (For X86) Enhancement to add-carray/sub-borrow (adc/sbb) optimization.
The adc/sbb optimization is to able to convert following expression
into a single adc/sbb instruction:
  (ult) ... = x + 1 // where the ult is unsigned-less-than comparison
  (ult) ... = x - 1

  This change is to flip the "x >u y" (i.e. ugt comparison) in order 
to expose the adc/sbb opportunity.

llvm-svn: 167180
2012-10-31 23:11:48 +00:00
Benjamin Kramer d724a590e5 X86: Add a bunch of peeps for add and sub of SETB.
"b + ((a < b) ? 1 : 0)" compiles into
	cmpl	%esi, %edi
	adcl	$0, %esi
instead of
	cmpl	%esi, %edi
	sbbl	%eax, %eax
	andl	$1, %eax
	addl	%esi, %eax

This saves a register, a false dependency on %eax
(Intel's CPUs still don't ignore it) and it's shorter.

llvm-svn: 131070
2011-05-08 18:36:07 +00:00
Chris Lattner 9edf3f50bf improve the setcc -> setcc_carry optimization to happen more
consistently by moving it out of lowering into dag combine.

Add some missing patterns for matching away extended versions of setcc_c.

llvm-svn: 122201
2010-12-19 22:08:31 +00:00
Owen Anderson f4b1a5bdc4 When adding the carry bit to another value on X86, exploit the fact that the carry-materialization
(sbbl x, x) sets the registers to 0 or ~0.  Combined with two's complement arithmetic, we can fold
the intermediate AND and the ADD into a single SUB.

This fixes <rdar://problem/8449754>.

llvm-svn: 114460
2010-09-21 18:41:19 +00:00