llvm-6502/lib/Transforms/Scalar
Chris Lattner 2e0d5f8432 Simplify and generalize the SROA "convert to scalar" transformation to
be able to handle *ANY* alloca that is poked by loads and stores of 
bitcasts and GEPs with constant offsets.  Before the code had a number
of annoying limitations and caused it to miss cases such as storing into
holes in structs and complex casts (as in bitfield-sroa) where we had
unions of bitfields etc.  This also handles a number of important cases
that are exposed due to the ABI lowering stuff we do to pass stuff by
value.

One case that is pretty great is that we compile 
2006-11-07-InvalidArrayPromote.ll into:

define i32 @func(<4 x float> %v0, <4 x float> %v1) nounwind {
	%tmp10 = call <4 x i32> @llvm.x86.sse2.cvttps2dq(<4 x float> %v1)
	%tmp105 = bitcast <4 x i32> %tmp10 to i128
	%tmp1056 = zext i128 %tmp105 to i256	
	%tmp.upgrd.43 = lshr i256 %tmp1056, 96
	%tmp.upgrd.44 = trunc i256 %tmp.upgrd.43 to i32	
	ret i32 %tmp.upgrd.44
}

which turns into:

_func:
	subl	$28, %esp
	cvttps2dq	%xmm1, %xmm0
	movaps	%xmm0, (%esp)
	movl	12(%esp), %eax
	addl	$28, %esp
	ret

Which is pretty good code all things considering :).

One effect of this is that SROA will start generating arbitrary bitwidth 
integers that are a multiple of 8 bits.  In the case above, we got a 
256 bit integer, but the codegen guys assure me that it can handle the 
simple and/or/shift/zext stuff that we're doing on these operations.

This addresses rdar://6532315



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63469 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-31 02:28:54 +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 Simplify the logic of getting hold of a PHI predecessor block. 2009-01-23 19:40:15 +00:00
CondPropagate.cpp Handle single-entry phi nodes gracefully in condprop. 2009-01-26 02:18:20 +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 Rename getABITypeSize to getTypePaddedSize, as 2009-01-12 20:38:59 +00:00
GVN.cpp improve compatibility with cygwin, patch by Jay Foad! 2009-01-19 22:00:18 +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 Fixed optimization of combining two shuffles where the first shuffle inputs 2009-01-26 04:39:00 +00:00
JumpThreading.cpp Fix PR3353, infinitely jump threading an infinite loop make from switches. 2009-01-19 21:20:34 +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 Rename getAnalysisToUpdate to getAnalysisIfAvailable. 2009-01-28 13:14:17 +00:00
LoopStrengthReduce.cpp Fix the time regression I introduced in 464.h264ref with 2009-01-14 02:35:31 +00:00
LoopUnroll.cpp Rename getAnalysisToUpdate to getAnalysisIfAvailable. 2009-01-28 13:14:17 +00:00
LoopUnswitch.cpp Rename getAnalysisToUpdate to getAnalysisIfAvailable. 2009-01-28 13:14:17 +00:00
Makefile Removed trailing whitespace from Makefiles. 2009-01-09 16:44:42 +00:00
MemCpyOptimizer.cpp Rename getABITypeSize to getTypePaddedSize, as 2009-01-12 20:38:59 +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 Simplify and generalize the SROA "convert to scalar" transformation to 2009-01-31 02:28:54 +00:00
SCCP.cpp Add the private linkage. 2009-01-15 20:18:42 +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 Fix copy and pasted typos that prevented strtok_r, realloc, getenv, ungetc, 2009-01-18 04:34:36 +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