Chris Lattner a92ff91a96 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 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122573 91177308-0d34-0410-b5e6-96231b3b80d8		2010-12-26 23:42:51 +00:00
..
ADCE
ArgumentPromotion
BlockPlacement
BranchFolding
CodeExtractor
CodeGenPrepare	revert r122164, I'm going to go with a different approach.	2010-12-19 04:23:03 +00:00
ConstantMerge
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
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
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
LoopSimplify
LoopStrengthReduce
LoopUnroll
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
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
SRETPromotion
StripSymbols
TailCallElim
TailDup