Chandler Carruth 9ef50ef1f7 Switch the lowering of CTLZ_ZERO_UNDEF from a .td pattern back to the ... X86ISelLowering C++ code. Because this is lowered via an xor wrapped around a bsr, we want the dagcombine which runs after isel lowering to have a chance to clean things up. In particular, it is very common to see code which looks like: (sizeof(x)*8 - 1) ^ __builtin_clz(x) Which is trying to compute the most significant bit of 'x'. That's actually the value computed directly by the 'bsr' instruction, but if we match it too late, we'll get completely redundant xor instructions. The more naive code for the above (subtracting rather than using an xor) still isn't handled correctly due to the dagcombine getting confused. Also, while here fix an issue spotted by inspection: we should have been expanding the zero-undef variants to the normal variants when there is an 'lzcnt' instruction. Do so, and test for this. We don't want to generate unnecessary 'bsr' instructions. These two changes fix some regressions in encoding and decoding benchmarks. However, there is still a *lot* to be improve on in this type of code. llvm-svn: 147244		2011-12-24 10:55:54 +00:00
..
Analysis	Make the unreachable probability much much heavier. The previous	2011-12-22 09:26:37 +00:00
Archive
Assembler	Add an explicit test of the auto-upgrade functionality for the new	2011-12-12 11:23:11 +00:00
Bindings/Ocaml
Bitcode
BugPoint
CodeGen	Switch the lowering of CTLZ_ZERO_UNDEF from a .td pattern back to the	2011-12-24 10:55:54 +00:00
DebugInfo	When recursing for the original size of a type, stop if we are at a	2011-12-16 23:42:45 +00:00
ExecutionEngine
Feature	The powers that be have decided that LLVM IR should now support 16-bit	2011-12-17 00:04:22 +00:00
Instrumentation/AddressSanitizer	[asan] add a test for instrumenting globals	2011-12-16 01:28:19 +00:00
Integer
lib
Linker	Now that PR11464 is fixed, reapply the patch to fix PR11464,	2011-12-20 00:12:26 +00:00
MC	ARM VFP assembly parsing and encoding for VCVT(float <--> fixed point).	2011-12-22 22:19:05 +00:00
Object
Other	Deleting the json-bench-test until I understand why it is flaky.	2011-12-17 06:29:32 +00:00
Scripts
TableGen
Transforms	Move this test from date-name to feature-name, and port it to FileCheck.	2011-12-23 18:41:31 +00:00
Unit
Verifier	Teach the verifier to reject all non-constant arguments to the second	2011-12-12 04:36:02 +00:00
CMakeLists.txt	Adds a JSON parser and a benchmark (json-bench) to catch performance regressions.	2011-12-16 13:09:10 +00:00
lit.cfg
lit.site.cfg.in
Makefile
Makefile.tests
site.exp.in
TestRunner.sh