Chris Lattner d4daf9f002 implement enough of the memset inference algorithm to recognize and insert ... memsets. This is still missing one important validity check, but this is enough to compile stuff like this: void test0(std::vector<char> &X) { for (std::vector<char>::iterator I = X.begin(), E = X.end(); I != E; ++I) *I = 0; } void test1(std::vector<int> &X) { for (long i = 0, e = X.size(); i != e; ++i) X[i] = 0x01010101; } With: $ clang t.cpp -S -o - -O2 -emit-llvm | opt -loop-idiom | opt -O3 | llc to: __Z5test0RSt6vectorIcSaIcEE: ## @_Z5test0RSt6vectorIcSaIcEE ## BB#0: ## %entry subq $8, %rsp movq (%rdi), %rax movq 8(%rdi), %rsi cmpq %rsi, %rax je LBB0_2 ## BB#1: ## %bb.nph subq %rax, %rsi movq %rax, %rdi callq ___bzero LBB0_2: ## %for.end addq $8, %rsp ret ... __Z5test1RSt6vectorIiSaIiEE: ## @_Z5test1RSt6vectorIiSaIiEE ## BB#0: ## %entry subq $8, %rsp movq (%rdi), %rax movq 8(%rdi), %rdx subq %rax, %rdx cmpq $4, %rdx jb LBB1_2 ## BB#1: ## %for.body.preheader andq $-4, %rdx movl $1, %esi movq %rax, %rdi callq _memset LBB1_2: ## %for.end addq $8, %rsp ret llvm-svn: 122573		2010-12-26 23:42:51 +00:00
..
ADCE
ArgumentPromotion	Make BasicAliasAnalysis a normal AliasAnalysis implementation which	2010-10-18 18:04:47 +00:00
BlockPlacement
BranchFolding
CodeExtractor
CodeGenPrepare	revert r122164, I'm going to go with a different approach.	2010-12-19 04:23:03 +00:00
ConstantMerge	fix PR8144, a bug where constant merge would merge globals marked	2010-09-15 00:30:11 +00:00
ConstProp	Teach ConstantFoldInstruction() how to fold insertvalue and extractvalue.	2010-11-29 20:36:52 +00:00
CorrelatedValuePropagation	Fix PR8790, another instance where unreachable code can cause instruction simplification to fail,	2010-12-15 00:55:35 +00:00
DeadArgElim
DeadStoreElimination	Fix PR8728, a miscompilation I recently introduced. When optimizing	2010-12-06 01:48:06 +00:00
FunctionAttrs	Make ModRefBehavior a lattice. Use this to clean up AliasAnalysis	2010-11-10 01:02:18 +00:00
GlobalDCE
GlobalOpt	reapply r121100 with a tweak to constant fold ConstExprs with TargetData	2010-12-07 04:33:29 +00:00
GVN	Give GVN back the ability to perform simple conditional propagation on conditional branch values.	2010-12-21 23:54:34 +00:00
IndVarSimplify	Remove LoopIndexSplit pass. It is neither maintained nor used by anyone.	2010-10-07 23:29:37 +00:00
Inline	when eliding a byval copy due to inlining a readonly function, we have	2010-12-20 08:10:40 +00:00
InstCombine	When determining if we can fold (x >> C1) << C2, the bits that we need to verify are zero	2010-12-23 23:56:24 +00:00
InstSimplify	When determining whether the new instruction was already present in	2010-12-22 17:15:25 +00:00
Internalize
IPConstantProp	more test cleanup	2010-09-02 22:38:56 +00:00
JumpThreading	Teach jump threading to "look through" a select when the branch direction of a terminator depends on it.	2010-12-15 09:51:20 +00:00
LCSSA
LICM	Enhance LICM to promote alias sets whose pointers themselves are stored,	2010-12-19 05:57:25 +00:00
LoopDeletion
LoopIdiom	implement enough of the memset inference algorithm to recognize and insert	2010-12-26 23:42:51 +00:00
LoopRotate	Teach loop rotate to hoist trivially invariant instructions	2010-09-06 01:10:22 +00:00
LoopSimplify	Fix LoopSimplify to notify ScalarEvolution when splitting a loop backedge	2010-09-04 02:42:48 +00:00
LoopStrengthReduce	Correct bogus module triple specifications.	2010-08-30 10:48:29 +00:00
LoopUnroll	Revert r113439, which relaxed the requirement that loops containing calls cannot be unrolled. After some discussion,	2010-09-09 20:02:23 +00:00
LoopUnswitch	Factor code for testing whether replacing one value with another	2010-11-18 19:59:41 +00:00
LowerAtomic
LowerInvoke
LowerSetJmp
LowerSwitch
Mem2Reg
MemCpyOpt	start using irbuilder to make mem intrinsics in a few passes.	2010-12-26 22:57:41 +00:00
MergeFunc
PartialSpecialize	Now using a variant of the existing inlining heuristics to decide whether to create a given specialization of a function in PartialSpecialization. If the total performance bonus across all callsites passing the same constant exceeds the specialization cost, we create the specialization.	2010-10-09 22:06:36 +00:00
PruneEH
Reassociate
ScalarRepl	Treat a call of function pointer like a load of the pointer when considering	2010-11-24 22:04:20 +00:00
SCCP
SimplifyCFG	SimplifyCFG: Ranges can be larger than 64 bits. Fixes Release-selfhost build.	2010-12-17 10:48:14 +00:00
SimplifyLibCalls	Revert r64460. strtol and friends cannot be marked readonly, even with	2010-12-17 01:09:43 +00:00
Sink	Make BasicAliasAnalysis a normal AliasAnalysis implementation which	2010-10-18 18:04:47 +00:00
SRETPromotion
StripSymbols
TailCallElim	merge two tests.	2010-08-31 18:44:03 +00:00
TailDup	The output of opt -stats must be sent to stderr. Patch by NAKAMURA Takumi!	2010-09-01 18:32:56 +00:00