Bob Wilson d79e684d1e Fix a minor bug in DAGCombiner's folding of SELECT. Folding "select C, 0, 1" ... to "C ^ 1" is only valid when C is known to be either 0 or 1. Most of the similar foldings in this function only handle "i1" types, but this one appears intentionally written to handle larger integer types. If C has an integer type larger than "i1", this needs to check if the high bits of a boolean are known to be zero. I also changed the comment to describe this folding as "C ^ 1" instead of "~C", since that is what the code does and since the latter would only be valid for "i1" types. The good news is that most LLVM targets use TargetLowering::ZeroOrOneBooleanContent so this change will not disable the optimization; the bad news is that I've been unable to come up with a testcase to demonstrate the problem. I have also removed a "FIXME" comment for folding "select C, X, 0" to "C & X", since the code looks correct to me. It could be made more aggressive by not limiting the type to "i1", but that would then require checking for TargetLowering::ZeroOrNegativeOneBooleanContent. Similar changes could be done for the other SELECT foldings, but it was decided to be not worth the trouble and complexity (see e.g., r44663). llvm-svn: 62790		2009-01-22 22:05:48 +00:00
..
Analysis	introduce a useful abstraction to find out if a Use is in the call position of an instruction	2009-01-22 21:35:57 +00:00
Archive	Add the private linkage.	2009-01-15 20:18:42 +00:00
AsmParser	Add the private linkage.	2009-01-15 20:18:42 +00:00
Bitcode	use specialized accessor instead of plain getOperand(0)	2009-01-16 18:40:27 +00:00
CodeGen	Fix a minor bug in DAGCombiner's folding of SELECT. Folding "select C, 0, 1"	2009-01-22 22:05:48 +00:00
Debugger	Removed trailing whitespace from Makefiles.	2009-01-09 16:44:42 +00:00
ExecutionEngine	Revert r62553 and r62616 due to issues with portability.	2009-01-22 20:09:20 +00:00
Linker	Add the private linkage.	2009-01-15 20:18:42 +00:00
Support	Do not use host floating point types when emitting	2009-01-21 20:32:55 +00:00
System	rename methods in System/Host to be more consistent.	2009-01-22 19:53:00 +00:00
Target	Add SelectionDAG::getNOT method to construct bitwise NOT operations,	2009-01-22 17:39:32 +00:00
Transforms	introduce a useful abstraction to find out if a Use is in the call position of an instruction	2009-01-22 21:35:57 +00:00
VMCore	Do not use host floating point types when emitting	2009-01-21 20:32:55 +00:00
Makefile	Removed trailing whitespace from Makefiles.	2009-01-09 16:44:42 +00:00