53 Commits

Author	SHA1	Message	Date
Benjamin Kramer	e739cf3eb5	X86: When combining shuffles just remove shuffles that are completely redundant. ... CombineTo doesn't allow replacing a node with itself so this would crash if the combined shuffle is the same as the input shuffle. llvm-svn: 212181	2014-07-02 15:09:44 +00:00
Chandler Carruth	688001f042	[x86] Teach the target combine step to aggressively fold pshufd insturcions. ... Summary: This allows it to fold pshufd instructions across intervening half-shuffles and other noise. This pattern actually shows up in the generic lowering tests, but I've also added direct tests using intrinsics to make sure that the specific desired functionality is working even if the lowering stuff changes in the future. Differential Revision: http://reviews.llvm.org/D4292 llvm-svn: 211892	2014-06-27 11:40:13 +00:00
Chandler Carruth	0d6d1f2b17	[x86] Teach the target-specific combining how to aggressively fold ... half-shuffles, even looking through intervening instructions in a chain. Summary: This doesn't happen to show up with any test cases I've found for the current shuffle lowering, but previous attempts would benefit from this and it seems generally useful. I've tested it directly using intrinsics, which also shows that it will work with hand vectorized code as well. Note that even though pshufd isn't directly used in these tests, it gets exercised because we combine some of the half shuffles into a pshufd first, and then merge them. Differential Revision: http://reviews.llvm.org/D4291 llvm-svn: 211890	2014-06-27 11:34:40 +00:00