Jakob Stoklund Olesen 0d5fcae6cd Defer some shl transforms to DAGCombine. ... The shl instruction is used to represent multiplication by a constant power of two as well as bitwise left shifts. Some InstCombine transformations would turn an shl instruction into a bit mask operation, making it difficult for later analysis passes to recognize the constsnt multiplication. Disable those shl transformations, deferring them to DAGCombine time. An 'shl X, C' instruction is now treated mostly the same was as 'mul X, C'. These transformations are deferred: (X >>? C) << C --> X & (-1 << C) (When X >> C has multiple uses) (X >>? C1) << C2 --> X << (C2-C1) & (-1 << C2) (When C2 > C1) (X >>? C1) << C2 --> X >>? (C1-C2) & (-1 << C2) (When C1 > C2) The corresponding exact transformations are preserved, just like div-exact + mul: (X >>?,exact C) << C --> X (X >>?,exact C1) << C2 --> X << (C2-C1) (X >>?,exact C1) << C2 --> X >>?,exact (C1-C2) The disabled transformations could also prevent the instruction selector from recognizing rotate patterns in hash functions and cryptographic primitives. I have a test case for that, but it is too fragile. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155136 91177308-0d34-0410-b5e6-96231b3b80d8		2012-04-19 16:46:26 +00:00
..
Analysis	Revert "SCEV: When expanding a GEP the final addition to the base pointer has NUW but not NSW."	2012-04-17 06:33:57 +00:00
Archive	Include cstdio in a few place that depended on getting it transitively through StringExtras.h	2012-03-23 11:35:30 +00:00
AsmParser	Convert assert(0) to llvm_unreachable	2012-02-07 05:05:23 +00:00
Bitcode	llvm::SwitchInst	2012-03-11 06:09:17 +00:00
CodeGen	Allow targets to select the default scheduler by name.	2012-04-19 01:34:10 +00:00
DebugInfo	Fix a C++11 UDL conflict.	2012-04-04 20:33:56 +00:00
ExecutionEngine	Fix incorrect call of resolveRelocation() for ARM ELF stub relocations.	2012-04-17 20:10:16 +00:00
Linker	It's possible for two types, which are isomorphic, to be added to the	2012-03-23 23:17:38 +00:00
MC	MC assembly parser handling for trailing comma in macro instantiation.	2012-04-16 21:18:49 +00:00
Object	Implement GDB integration for source level debugging of code JITed using	2012-04-16 22:12:58 +00:00
Support	SourceMgr: Colorize diagnostics.	2012-04-18 19:04:15 +00:00
TableGen	Fix copy/paste-o.	2012-04-18 18:09:53 +00:00
Target	zap tabs	2012-04-19 15:16:31 +00:00
Transforms	Defer some shl transforms to DAGCombine.	2012-04-19 16:46:26 +00:00
VMCore	Remove AVX vpermil intrinsics. I removed their uses from clang headers and builtins a while back.	2012-04-18 05:24:00 +00:00
CMakeLists.txt	Move TableGen's parser and entry point into a library	2011-10-01 16:41:13 +00:00
LLVMBuild.txt	LLVMBuild: Introduce a common section which currently has a list of the	2011-12-12 22:45:54 +00:00
Makefile	Remove more of llvmc and dependencies.	2011-09-20 00:34:27 +00:00