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llvm-mirror/test/CodeGen
Chris Lattner be0c5a0500 Fix a long standing deficiency in the X86 backend: we would
sometimes emit "zero" and "all one" vectors multiple times,
for example:

_test2:
	pcmpeqd	%mm0, %mm0
	movq	%mm0, _M1
	pcmpeqd	%mm0, %mm0
	movq	%mm0, _M2
	ret

instead of:

_test2:
	pcmpeqd	%mm0, %mm0
	movq	%mm0, _M1
	movq	%mm0, _M2
	ret

This patch fixes this by always arranging for zero/one vectors
to be defined as v4i32 or v2i32 (SSE/MMX) instead of letting them be
any random type.  This ensures they get trivially CSE'd on the dag.
This fix is also important for LegalizeDAGTypes, as it gets unhappy
when the x86 backend wants BUILD_VECTOR(i64 0) to be legal even when
'i64' isn't legal.

This patch makes the following changes:

1) X86TargetLowering::LowerBUILD_VECTOR now lowers 0/1 vectors into
   their canonical types.
2) The now-dead patterns are removed from the SSE/MMX .td files.
3) All the patterns in the .td file that referred to immAllOnesV or
   immAllZerosV in the wrong form now use *_bc to match them with a
   bitcast wrapped around them.
4) X86DAGToDAGISel::SelectScalarSSELoad is generalized to handle 
   bitcast'd zero vectors, which simplifies the code actually.
5) getShuffleVectorZeroOrUndef is updated to generate a shuffle that
   is legal, instead of generating one that is illegal and expecting
   a later legalize pass to clean it up.
6) isZeroShuffle is generalized to handle bitcast of zeros.
7) several other minor tweaks.

This patch is definite goodness, but has the potential to cause random
code quality regressions.  Please be on the lookout for these and let 
me know if they happen.

llvm-svn: 44310
2007-11-25 00:24:49 +00:00
..
Alpha Convert tests using "| wc -l | grep ..." to use the count script. 2007-08-15 13:36:28 +00:00
ARM [ARM] Implement __builtin_thread_pointer. 2007-11-08 17:20:05 +00:00
CBackend Change all floating constants that are not exactly 2007-09-05 17:50:36 +00:00
Generic Fix a bug in which node A is replaced by node B, but later 2007-11-21 16:43:19 +00:00
IA64 Convert .cvsignore files 2007-06-29 16:35:07 +00:00
PowerPC Testcase for PR1811 2007-11-19 21:43:22 +00:00
SPARC Convert tests using "| wc -l | grep ..." to use the count script. 2007-08-15 13:36:28 +00:00
X86 Fix a long standing deficiency in the X86 backend: we would 2007-11-25 00:24:49 +00:00