failing to form a memset, then having to delete it" but my approximation
isn't safe for self recurrent loops.  Instead of doign a hack, just
do it the right way.

llvm-svn: 131858

Add a parameter to ConstantFoldTerminator() that callers can use to ask it to also clean up the condition of any conditional terminator it folds to be unconditional, if that turns the condition into dead code. This just means it calls RecursivelyDeleteTriviallyDeadInstructions() in strategic spots. It defaults to the old behavior.

I also changed -simplifycfg, -jump-threading and -codegenprepare to use this to produce slightly better code without any extra cleanup passes (AFAICT this was the only place in -simplifycfg where now-dead conditions of replaced terminators weren't being cleaned up). The only other user of this function is -sccp, but I didn't read that thoroughly enough to figure out whether it might be holding pointers to instructions that could be deleted by this.

llvm-svn: 131855

causing it to get into infinite loops when it would widen a 
load (which can necessarily leave around dead loads).

llvm-svn: 131847

consistently.

llvm-svn: 131803

No functionality enabled by default. Use -disable-iv-rewrite.
Extended IVUsers to keep track of the phi that represents the users' IV.
Added the WidenIV transform to replace a narrow IV with a wide IV
by doing a one-for-one replacement of IV users instead of expanding the
SCEV expressions. [sz]exts are removed and truncs are inserted.

llvm-svn: 131744

llvm-svn: 131716

of the comparison, so that the resulting expression is fully
normalized. This fixes PR9939.

llvm-svn: 131576

Original log entry:
Refactor getActionType and getTypeToTransformTo ; place all of the 'decision'
code in one place.

llvm-svn: 131536

code in one place.

llvm-svn: 131534

llvm-svn: 131482

llvm-svn: 131481

corrupted when setjmp returns again.

llvm-svn: 131399

the users.

llvm-svn: 131277

Interleave IV simplifications. Currently involves EliminateComparison
and EliminateRemainder. Next I'll add EliminateExtend.

llvm-svn: 131210

return the pointer being dereferenced, it returns the pointee, but a call
might return the pointer itself.

llvm-svn: 130979

llvm-svn: 130895

llvm-svn: 130880

llvm-svn: 130876

llvm-svn: 130869

This adds functionality to remove size/zero extension during indvars
without generating a canonical IV and rewriting all IV users. It's
disabled by default so should have no effect on codegen. Work in progress.

llvm-svn: 130829

Only create a canonical IV for backedge taken count if it will
actually be used by LinearFunctionTestReplace. And some related
cleanup, preparing to reduce dependence on canonical IVs.
No significant effect on x86 or arm in the test-suite.

llvm-svn: 130799

model constants which can be added to base registers via add-immediate
instructions which don't require an additional register to materialize
the immediate.

llvm-svn: 130743

problem reported on cfe-dev.

llvm-svn: 130661

llvm-svn: 130536

llvm-svn: 130450

llvm-svn: 130426

llvm-svn: 130419

a nice and tidy:
  %x1 = load i32* %0, align 4
  %1 = icmp eq i32 %x1, 1179403647
  br i1 %1, label %if.then, label %if.end

instead of doing lots of loads and branches.  May the FreeBSD bootloader
long fit in its allocated space.

llvm-svn: 130416

llvm-svn: 130414

llvm-svn: 130408

static functions instead of passing around tons of random ivars.

llvm-svn: 130403

llvm-svn: 130401

wider load would allow elimination of subsequent loads, and when the wider
load is still a native integer type.  This eliminates a ton of loads on 
various benchmarks involving struct fields, though it is somewhat hobbled
by clang not being very aggressive about field alignment.

This is yet another step along the way towards resolving PR6627.

llvm-svn: 130390

llvm-svn: 130350

Modified LinearFunctionTestReplace to push the condition on the dead
list instead of eagerly deleting it. This can cause unnecessary
IV rewrites, which should have no effect on codegen and will not be an
issue once we stop generating canonical IVs.

llvm-svn: 130340

Simplify cfg inserts a call to trap when unreachable code is detected. Assign DebugLoc to this new trap instruction.

llvm-svn: 130315

translation fails.  We were bailing out in some cases that would
cause us to miss GVN'ing some non-local cases away.

llvm-svn: 130206

return it as a clobber.  This allows GVN to do smart things.

Enhance GVN to be smart about the case when a small load is clobbered
by a larger overlapping load.  In this case, forward the value.  This
allows us to compile stuff like this:

int test(void *P) {
  int tmp = *(unsigned int*)P;
  return tmp+*((unsigned char*)P+1);
}

into:

_test:                                  ## @test
	movl	(%rdi), %ecx
	movzbl	%ch, %eax
	addl	%ecx, %eax
	ret

which has one load.  We already handled the case where the smaller
load was from a must-aliased base pointer.

llvm-svn: 130180

llvm-svn: 130068

generated by llvm-gcc, since llvm-gcc uses 2 i64s for passing a 4 x float
vector on ARM rather than an i64 array like Clang.

llvm-svn: 129878