llvm-6502/lib/Transforms/Scalar
Chris Lattner d2fa781169 Implement the first half of PR3290: if there is a store of an
integer to a (transitive) bitcast the alloca and if that integer
has the full size of the alloca, then it clobbers the whole thing.
Handle this by extracting pieces out of the stored integer and 
filing them away in the SROA'd elements.

This triggers fairly frequently because the CFE uses integers to
pass small structs by value and the inliner exposes these.  For 
example, in kimwitu++, I see a bunch of these with i64 stores to
"%struct.std::pair<std::_Rb_tree_const_iterator<kc::impl_abstract_phylum*>,bool>"

In 176.gcc I see a few i32 stores to "%struct..0anon".

In the testcase, this is a difference between compiling test1 to:

_test1:
	subl	$12, %esp
	movl	20(%esp), %eax
	movl	%eax, 4(%esp)
	movl	16(%esp), %eax
	movl	%eax, (%esp)
	movl	(%esp), %eax
	addl	4(%esp), %eax
	addl	$12, %esp
	ret

vs:

_test1:
	movl	8(%esp), %eax
	addl	4(%esp), %eax
	ret

The second half of this will be to handle loads of the same form.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61853 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-07 08:11:13 +00:00
..
ADCE.cpp Let instcombiner remove redundant dbg intrinsics. 2008-11-19 18:59:41 +00:00
BasicBlockPlacement.cpp Tidy up several unbeseeming casts from pointer to intptr_t. 2008-09-04 17:05:41 +00:00
CMakeLists.txt CMake: updated list of source files. 2008-11-05 00:11:22 +00:00
CodeGenPrepare.cpp Find loop back edges only after empty blocks are eliminated. 2009-01-05 21:17:27 +00:00
CondPropagate.cpp Factor some code into a new FoldSingleEntryPHINodes method. 2008-12-03 19:44:02 +00:00
ConstantProp.cpp Tidy up several unbeseeming casts from pointer to intptr_t. 2008-09-04 17:05:41 +00:00
DCE.cpp simplify this logic. 2008-11-27 22:46:09 +00:00
DeadStoreElimination.cpp don't bother touching volatile stores, they will just return clobber on 2008-12-07 00:25:15 +00:00
GVN.cpp Don't forget to remove phi nodes from the value numbering table after we collapse them. 2008-12-23 00:49:51 +00:00
GVNPRE.cpp Tidy up several unbeseeming casts from pointer to intptr_t. 2008-09-04 17:05:41 +00:00
IndVarSimplify.cpp Revert r60042. IndVarSimplify should check if APFloat is PPCDoubleDouble first before trying to convert it to an integer. 2008-11-26 01:11:57 +00:00
InstructionCombining.cpp Change m_ConstantInt and m_SelectCst to take their constant integers 2009-01-05 23:53:12 +00:00
JumpThreading.cpp remove DebugIterations option. Despite the accusations, 2008-12-08 22:44:07 +00:00
LICM.cpp Change create*Pass factory functions to return Pass* instead of 2008-10-22 23:32:42 +00:00
LoopDeletion.cpp Change create*Pass factory functions to return Pass* instead of 2008-10-22 23:32:42 +00:00
LoopIndexSplit.cpp Fix spelling. 2008-12-08 17:07:24 +00:00
LoopRotation.cpp Change create*Pass factory functions to return Pass* instead of 2008-10-22 23:32:42 +00:00
LoopStrengthReduce.cpp Revert 61362 and 61402 until SPEC breakage is fixed. 2008-12-23 23:21:35 +00:00
LoopUnroll.cpp Change create*Pass factory functions to return Pass* instead of 2008-10-22 23:32:42 +00:00
LoopUnswitch.cpp Undo previous patch. 2008-12-08 17:02:37 +00:00
Makefile remove attribution from lib Makefiles. 2007-12-29 20:09:26 +00:00
MemCpyOptimizer.cpp Make a few major changes to memdep and its clients: 2008-12-05 21:04:20 +00:00
PredicateSimplifier.cpp Silence unused variable warnings. 2008-11-21 20:00:59 +00:00
Reassociate.cpp Fix build failure. 2008-11-21 21:00:20 +00:00
Reg2Mem.cpp Tidy up several unbeseeming casts from pointer to intptr_t. 2008-09-04 17:05:41 +00:00
Scalar.cpp C and Objective Caml bindings for mem2reg and reg2mem. 2008-03-20 17:16:03 +00:00
ScalarReplAggregates.cpp Implement the first half of PR3290: if there is a store of an 2009-01-07 08:11:13 +00:00
SCCP.cpp Fix unused variable warnings. 2008-11-21 01:52:59 +00:00
SimplifyCFGPass.cpp Large mechanical patch. 2008-09-25 21:00:45 +00:00
SimplifyHalfPowrLibCalls.cpp eliminate warning when asserts disabled. 2008-12-14 21:36:23 +00:00
SimplifyLibCalls.cpp Move the libcall annotating part from doFinalization to doInitialization. 2009-01-05 00:07:50 +00:00
TailDuplication.cpp simplify code. 2008-11-27 22:56:14 +00:00
TailRecursionElimination.cpp Tidy up several unbeseeming casts from pointer to intptr_t. 2008-09-04 17:05:41 +00:00