Commit Graph

428 Commits

Author SHA1 Message Date
Eli Friedman 7e1716dc9d Canonicalize boolean +/- a constant to a select.
(I think it's reasonably clear that we want to have a canonical form for 
constructs like this; if anyone thinks that a select is not the best 
canonical form, please tell me.)

llvm-svn: 75531
2009-07-13 22:27:52 +00:00
Chris Lattner edb8407f0c do not try to analyze bitcasts from i64 to <2 x i32> in ComputedMaskedBits. While
we could do this, doing so requires adjusting the demanded mask and the code isn't 
doing that yet.  This fixes PR4495

llvm-svn: 74699
2009-07-02 16:04:08 +00:00
Dan Gohman 83348f80b6 Fix an instcombine abort on a scalar-to-vector bitcast. This fixes PR4487.
llvm-svn: 74646
2009-07-01 21:38:46 +00:00
Dan Gohman 56bd02c55c Generalize the zext(trunc(t) & C) instcombine to work even with
C is not a low-bits mask, and add a similar instcombine for
zext((trunc(t) & C) ^ C).

llvm-svn: 73705
2009-06-18 16:30:21 +00:00
Dan Gohman 7f836c7c61 Instcombine zext(trunc(x) & mask) to x&mask, even if the trunc has
multiple users.

llvm-svn: 73656
2009-06-17 23:17:05 +00:00
Eli Friedman 28891b661d Correct an accidental duplication of the test (patch doesn't handle
creating new files very well).

llvm-svn: 73599
2009-06-17 03:05:00 +00:00
Eli Friedman a0fba5319d PR3439: Correct a silly mistake in the SimplifyDemandedUseBits code for
SRem.

llvm-svn: 73598
2009-06-17 02:57:36 +00:00
Dan Gohman 0ed7756fbe Generalize a few more instcombines to be vector/scalar-independent.
llvm-svn: 73541
2009-06-16 19:55:29 +00:00
Chris Lattner 22c645b337 Testcase for r73506
llvm-svn: 73508
2009-06-16 17:23:25 +00:00
Dan Gohman 7ccc52f131 Support vector casts in more places, fixing a variety of assertion
failures.

To support this, add some utility functions to Type to help support
vector/scalar-independent code. Change ConstantInt::get and
ConstantFP::get to support vector types, and add an overload to
ConstantInt::get that uses a static IntegerType type, for
convenience.

Introduce a new getConstant method for ScalarEvolution, to simplify
common use cases.

llvm-svn: 73431
2009-06-15 22:12:54 +00:00
Chris Lattner 1c0db34815 fix testcase to properly check for the patch in r73195.
llvm-svn: 73380
2009-06-15 05:46:02 +00:00
Dan Gohman 9377b086f5 Don't do (x - (y - z)) --> (x + (z - y)) on floating-point types, because
it may round differently. This fixes PR4374.

llvm-svn: 73243
2009-06-12 19:23:25 +00:00
Chris Lattner 61797e3291 Fix 4366: store to null in non-default addr space should not be
turned into unreachable.

llvm-svn: 73195
2009-06-11 17:54:56 +00:00
Eli Friedman 73a83066d5 PR4340: Run SimplifyDemandedVectorElts on insertelement instructions;
sometimes it can find simplifications that won't be found otherwise.

llvm-svn: 73006
2009-06-06 20:08:03 +00:00
Dan Gohman a5b9645c4b Split the Add, Sub, and Mul instruction opcodes into separate
integer and floating-point opcodes, introducing
FAdd, FSub, and FMul.

For now, the AsmParser, BitcodeReader, and IRBuilder all preserve
backwards compatability, and the Core LLVM APIs preserve backwards
compatibility for IR producers. Most front-ends won't need to change
immediately.

This implements the first step of the plan outlined here:
http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt

llvm-svn: 72897
2009-06-04 22:49:04 +00:00
Dan Gohman 1aa86203f6 Check in test changes that I accidentally left out of r72872.
llvm-svn: 72875
2009-06-04 18:22:31 +00:00
Evan Cheng a838a40bc4 Fix bug in FoldFCmp_IntToFP_Cst. If inttofp is a uintofp, use unsigned instead of signed integer constant.
llvm-svn: 72300
2009-05-22 23:10:53 +00:00
Dan Gohman bf0002e7c1 Teach ValueTracking a new way to analyze PHI nodes, and and teach
Instcombine to be more aggressive about using SimplifyDemandedBits
on shift nodes. This allows a shift to be simplified to zero in the
included test case.

llvm-svn: 72204
2009-05-21 02:28:33 +00:00
Chris Lattner 149546a6a0 calls in nothrow functions can be marked nothrow even if the callee
is not known to be nothrow.  This allows readnone/readonly functions
to be deleted even if we don't know whether the callee can throw.

llvm-svn: 71676
2009-05-13 17:39:14 +00:00
Dan Gohman 4bb6fa23cb Revert 71165. It did more than just revert 71158 and it introduced
several regressions. The problem due to 71158 is now fixed.

llvm-svn: 71176
2009-05-07 19:46:24 +00:00
Bill Wendling 17f0f65499 Temporarily revert r71158. It was causing a failure during a full bootstrap:
checking for bcopy... no
checking for getc_unlocked... Assertion failed: (0 && "Unknown SCEV kind!"), function operator(), file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/Analysis/ScalarEvolution.cpp, line 511.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/libdecnumber/decUtility.c:360: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
make[4]: *** [decUtility.o] Error 1
make[4]: *** Waiting for unfinished jobs....
Assertion failed: (0 && "Unknown SCEV kind!"), function operator(), file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/Analysis/ScalarEvolution.cpp, line 511.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/libdecnumber/decNumber.c:5591: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
make[4]: *** [decNumber.o] Error 1
make[3]: *** [all-stage2-libdecnumber] Error 2
make[3]: *** Waiting for unfinished jobs....

llvm-svn: 71165
2009-05-07 17:26:14 +00:00
Dan Gohman e5d2a04ace Constant-fold ptrtoint+add+inttoptr to gep when the pointer is an
array and the add is within range. This helps simplify expressions
expanded by ScalarEvolutionExpander.

llvm-svn: 71158
2009-05-07 14:24:56 +00:00
Dan Gohman 5638e0d642 Add several more icmp simplifications. Transform signed comparisons
into unsigned ones when the operands are known to have the same
sign bit value.

llvm-svn: 70053
2009-04-25 17:12:48 +00:00
Chris Lattner 184f1be4a8 Add a new "available_externally" linkage type. This is intended
to support C99 inline, GNU extern inline, etc.  Related bugzilla's
include PR3517, PR3100, & PR2933.  Nothing uses this yet, but it
appears to work.

llvm-svn: 68940
2009-04-13 05:44:34 +00:00
Chris Lattner eb510d6b3d Instcombine should not promote whole computation trees to "strange"
integer types, unless they are already strange.  This prevents it from
turning the code produced by SROA into crazy libcalls and stuff that 
the code generator can't handle.  In the attached example, the result
was an i96 multiply that caused the x86 backend to assert.

Note that if TargetData had an idea of what the legal types are for
a target that this could be used to stop instcombine from introducing
i64 muls, as Scott wanted.

llvm-svn: 68598
2009-04-08 05:41:03 +00:00
Chris Lattner 321741af5f fix rdar://6762290, a crash compiling cxx filt with clang.
llvm-svn: 68500
2009-04-07 05:03:34 +00:00
Evan Cheng 826b6f0f7c Throttle back "fold select into operand" transformation. InstCombine should not generate selects of two constants unless they are selects of 0 and 1.
e.g.
define i32 @t1(i32 %c, i32 %x) nounwind {
       %t1 = icmp eq i32 %c, 0
       %t2 = lshr i32 %x, 18
       %t3 = select i1 %t1, i32 %t2, i32 %x
       ret i32 %t3
}

was turned into

define i32 @t2(i32 %c, i32 %x) nounwind {
       %t1 = icmp eq i32 %c, 0
       %t2 = select i1 %t1, i32 18, i32 0
       %t3 = lshr i32 %x, %t2
       ret i32 %t3
}

For most targets, that means materializing two constants and then a select. e.g. On x86-64

movl    %esi, %eax
shrl    $18, %eax
testl   %edi, %edi
cmovne  %esi, %eax
ret

=>

xorl    %eax, %eax
testl   %edi, %edi
movl    $18, %ecx
cmovne  %eax, %ecx
movl    %esi, %eax
shrl    %cl, %eax
ret

Also, the optimizer and codegen can reason about shl / and / add, etc. by a constant. This optimization will hinder optimizations using ComputeMaskedBits.

llvm-svn: 68142
2009-03-31 20:42:45 +00:00
Chris Lattner c3b2111d97 Fix PR3874 by restoring a condition I removed, but making it more
precise than it used to be.

llvm-svn: 67662
2009-03-25 00:28:58 +00:00
Chris Lattner 306813cbbb canonicalize inttoptr and ptrtoint instructions which cast pointers
to/from integer types that are not intptr_t to convert to intptr_t
then do an integer conversion to the dest type.  This exposes the
cast to the optimizer.

llvm-svn: 67638
2009-03-24 18:35:40 +00:00
Chris Lattner d9eb41177a two changes:
1. Make instcombine always canonicalize trunc x to i1 into an icmp(x&1).  This 
   exposes the AND to other instcombine xforms and is more of what the code
   generator expects.
2. Rewrite the remaining trunc pattern match to use 'match', which 
   simplifies it a lot.
   

llvm-svn: 67635
2009-03-24 18:15:30 +00:00
Chris Lattner 0a981d1d36 Fix instcombine to not introduce undefined shifts when merging two
shifts together.  This fixes PR3851.

llvm-svn: 67411
2009-03-20 22:41:15 +00:00
Chris Lattner 595923ff75 Fix PR3826 - InstComb assert with vector shift, by not calling ComputeNumSignBits on a vector.
llvm-svn: 67211
2009-03-18 16:32:19 +00:00
Duncan Sands 5795a6091d Fix PR3694: add an instcombine micro-optimization that helps
clean up when using variable length arrays in llvm-gcc.

llvm-svn: 65832
2009-03-02 09:18:21 +00:00
Chris Lattner af618171f4 Fix PR3667
llvm-svn: 65464
2009-02-25 18:20:01 +00:00
Dan Gohman 3204dac652 Add a testcase for the problem fixed in r65289.
llvm-svn: 65365
2009-02-24 02:17:42 +00:00
Dan Gohman 4f356bb9b0 Fix a ValueTracking rule: RHS means operand 1, not 0. Add a simple
ashr instcombine to help expose this code. And apply the fix to
SelectionDAG's copy of this code too.

llvm-svn: 65364
2009-02-24 02:00:40 +00:00
Nick Lewycky d44e80d7fc Don't sign extend the char when expanding char -> int during
load(bitcast(char[4] to i32*)) evaluation.

llvm-svn: 65246
2009-02-21 20:50:42 +00:00
Chris Lattner bef6b2098e rename a function to indicate that it checks for profitability as well
as legality.  Make load sinking and gep sinking more careful: we only
do it when it won't pessimize loads from the stack.  This has the added
benefit of not producing code that is unanalyzable to SROA.

llvm-svn: 65209
2009-02-21 00:46:50 +00:00
Dan Gohman b694533a54 Change the argument type in this test to something less convoluted,
since it isn't actually used. 

llvm-svn: 64883
2009-02-18 04:25:04 +00:00
Chris Lattner 24f31a0e59 commit a tweaked version of Daniel's patch for PR3599. We now
eliminate all the extensions and all but the one required truncate
from the testcase, but the or/and/shift stuff still isn't zapped.

llvm-svn: 64809
2009-02-17 20:47:23 +00:00
Dan Gohman f68d29edd5 Fix EnforceKnownAlignment so that it doesn't ever reduce the alignment
of an alloca or global variable.

llvm-svn: 64693
2009-02-16 23:02:21 +00:00
Dan Gohman 9cdfd44521 Change these tests to use regular loads instead of llvm.x86.sse2.loadu.dq.
Enhance instcombine to use the preferred field of
GetOrEnforceKnownAlignment in more cases, so that regular IR operations are
optimized in the same way that the intrinsics currently are.

llvm-svn: 64623
2009-02-16 00:44:23 +00:00
Nate Begeman 94aa38d568 Add suppport for ConstantExprs of shufflevectors whose result type is not equal to the
type of the vectors being shuffled.

llvm-svn: 64401
2009-02-12 21:28:33 +00:00
Mon P Wang 21eb52a74f Instrcombine should not change load(cast p) to cast(load p) if the cast
changes the address space of the pointer.

llvm-svn: 64035
2009-02-07 22:19:29 +00:00
Duncan Sands e7d5479136 Allow the inverse transform x86_fp80 -> i80 (also
fires during the Ada build).

llvm-svn: 63731
2009-02-04 11:17:06 +00:00
Duncan Sands 1ea1173143 Fix PR3468: a crash when constant folding a bitcast of
i80 to x86 long double (this was presumably generated
by sroa).

llvm-svn: 63730
2009-02-04 10:17:14 +00:00
Evan Cheng 8542caa3f7 APInt'fy SimplifyDemandedVectorElts so it can analyze vectors with more than 64 elements.
llvm-svn: 63631
2009-02-03 10:05:09 +00:00
Chris Lattner c4eb63d412 reduce testcase.
llvm-svn: 63499
2009-02-02 06:55:45 +00:00
Nick Lewycky f23908151a Reinstate this optimization to fold icmp of xor when possible. Don't try to
turn icmp eq a+x, b+x into icmp eq a, b if a+x or b+x has other uses. This
may have been increasing register pressure leading to the bzip2 slowdown.

llvm-svn: 63487
2009-01-31 21:30:05 +00:00
Chris Lattner 9e2b9f3234 Fix PR3452 (an infinite loop bootstrapping) by disabling the recent
improvements to the EvaluateInDifferentType code.  This code works 
by just inserted a bunch of new code and then seeing if it is 
useful.  Instcombine is not allowed to do this: it can only insert
new code if it is useful, and only when it is converging to a more
canonical fixed point.  Now that we iterate when DCE makes progress,
this causes an infinite loop when the code ends up not being used.

llvm-svn: 63483
2009-01-31 19:05:27 +00:00
Chris Lattner 76a63ed099 now that all the pieces are in place, teach instcombine's
simplifydemandedbits to simplify instructions with *multiple
uses* in contexts where it can get away with it.  This allows
it to simplify the code in multi-use-or.ll into a single 'add 
double'.

This change is particularly interesting because it will cover
up for some common codegen bugs with large integers created due
to the recent SROA patch.  When working on fixing those bugs,
this should be disabled.

llvm-svn: 63481
2009-01-31 08:40:03 +00:00
Chris Lattner 94cfb281c3 make sure to set Changed=true when instcombine hacks on the code,
not doing so prevents it from properly iterating and prevents it
from deleting the entire body of dce-iterate.ll

llvm-svn: 63476
2009-01-31 07:04:22 +00:00
Mon P Wang 3537a62704 Fixed optimization of combining two shuffles where the first shuffle inputs
has a different number of elements than the output.

llvm-svn: 62998
2009-01-26 04:39:00 +00:00
Torok Edwin f4395ea97a testcase for PR3381.
Also it was an empty struct, not a void after all.

llvm-svn: 62920
2009-01-24 17:16:04 +00:00
Chris Lattner 72cd68fe64 Make InstCombineStoreToCast handle aggregates more aggressively,
handling the case in Transforms/InstCombine/cast-store-gep.ll, which
is a heavily reduced testcase from Clang on x86-64.

llvm-svn: 62904
2009-01-24 01:00:13 +00:00
Dale Johannesen 1f86498f93 Do not use host floating point types when emitting
ASCII IR; loading and storing these can change the
bits of NaNs on some hosts.  Remove or add warnings
at a few other places using host floating point;
this is a bad thing to do in general.

llvm-svn: 62712
2009-01-21 20:32:55 +00:00
Dale Johannesen 287b4bc44e Disable on x86_64 until I figure out what's wrong.
llvm-svn: 62660
2009-01-21 02:08:30 +00:00
Dale Johannesen b5721632ee Make special cases (0 inf nan) work for frem.
Besides APFloat, this involved removing code
from two places that thought they knew the
result of frem(0., x) but were wrong.

llvm-svn: 62645
2009-01-21 00:35:19 +00:00
Dale Johannesen e75fdb0510 Calls to fmod, it turns out, are constant-folded by
invoking the host fmod, not by lowering to frem and
constant-folding that.  Fix this so it tests what I
want to test.

llvm-svn: 62622
2009-01-20 21:58:13 +00:00
Dale Johannesen d067ecd1c7 Move & restructure test per review.
llvm-svn: 62538
2009-01-19 22:33:12 +00:00
Chris Lattner db2d9613d2 Fix PR3335 by not turning a store to one address space into a store to another.
llvm-svn: 62351
2009-01-16 20:12:52 +00:00
Evan Cheng beac6f8b0c Clean up previous cast optimization a bit. Also make zext elimination a bit more aggressive: if it's not necessary to emit an AND (i.e. high bits are already zero), it's profitable to evaluate the operand at a different type.
llvm-svn: 62297
2009-01-16 02:11:43 +00:00
Evan Cheng 60e19a46f2 - Teach CanEvaluateInDifferentType of this xform: sext (zext ty1), ty2 -> zext ty2
- Looking at the number of sign bits of the a sext instruction to determine  whether new trunc + sext pair should be added when its source is being evaluated in a different type.

llvm-svn: 62263
2009-01-15 17:01:23 +00:00
Dan Gohman 59af77376c Make instcombine ensure that all allocas are explicitly aligned at at
least their preferred alignment.

llvm-svn: 62176
2009-01-13 20:18:38 +00:00
Chris Lattner f50aa6ae5c Implement rdar://6480391, extending of equality icmp's to avoid a truncation.
I noticed this in the code compiled for a routine using std::map, which produced
this code:
	%25 = tail call i32 @memcmp(i8* %24, i8* %23, i32 6) nounwind readonly
	%.lobit.i = lshr i32 %25, 31		; <i32> [#uses=1]
	%tmp.i = trunc i32 %.lobit.i to i8		; <i8> [#uses=1]
	%toBool = icmp eq i8 %tmp.i, 0		; <i1> [#uses=1]
	br i1 %toBool, label %bb3, label %bb4
which compiled to:

	call	L_memcmp$stub
	shrl	$31, %eax
	testb	%al, %al
	jne	LBB1_11	## 

with this change, we compile it to:

	call	L_memcmp$stub
	testl	%eax, %eax
	js	LBB1_11

This triggers all the time in common code, with patters like this:

	%169 = and i32 %ply, 1		; <i32> [#uses=1]
	%170 = trunc i32 %169 to i8		; <i8> [#uses=1]
	%toBool = icmp ne i8 %170, 0		; <i1> [#uses=1]

 	%7 = lshr i32 %6, 24		; <i32> [#uses=1]
	%9 = trunc i32 %7 to i8		; <i8> [#uses=1]
	%10 = icmp ne i8 %9, 0		; <i1> [#uses=1]

etc

llvm-svn: 61985
2009-01-09 07:47:06 +00:00
Chris Lattner fef138b140 Fix part 3/2 of PR3290, making instcombine zap (gep(bitcast)) when possible.
llvm-svn: 61980
2009-01-09 05:44:56 +00:00
Chris Lattner f3e696bc5a ValueTracker can't assume that an alloca with no specified alignment
will get its preferred alignment.  It has to be careful and cautiously assume
it will just get the ABI alignment.  This prevents instcombine from rounding
up the alignment of a load/store without adjusting the alignment of the alloca.

llvm-svn: 61934
2009-01-08 19:28:38 +00:00
Chris Lattner 4e735eb157 make m_ConstantInt(int64_t) safely match ConstantInt's that are larger than i64.
This fixes an instcombine crash on PR3235.

llvm-svn: 61775
2009-01-05 23:45:50 +00:00
Bill Wendling 0a09d2de13 XFAIL this test. The xform was removed.
llvm-svn: 61624
2009-01-04 06:32:28 +00:00
Bill Wendling aedb54a947 Add transformation:
xor (or (icmp, icmp), true) -> and(icmp, icmp)

This is possible because of De Morgan's law.

llvm-svn: 61537
2009-01-01 01:18:23 +00:00
Nick Lewycky 0f0e63fe73 Make all the vector elements positive in an srem of constant vector.
llvm-svn: 61195
2008-12-18 06:31:11 +00:00
Bill Wendling 582fe6b0ca Use m_Specific() instead of double matching.
llvm-svn: 60341
2008-12-01 08:09:47 +00:00
Chris Lattner 9e6b243428 simplify these patterns using m_Specific. No need to grep for
xor in testcase (or is a substring).

llvm-svn: 60328
2008-12-01 05:16:26 +00:00
Chris Lattner 9d02a70a7d Teach inst combine to merge GEPs through PHIs. This is really
important because it is sinking the loads using the GEPs, but
not the GEPs themselves.  This triggers 647 times on 403.gcc
and makes the .s file much much nicer.  For example before:

        je      LBB1_87 ## bb78
LBB1_62:        ## bb77
        leal    84(%esi), %eax
LBB1_63:        ## bb79
        movl    (%eax), %eax
...
LBB1_87:        ## bb78
        movl    $0, 4(%esp)
        movl    %esi, (%esp)
        call    L_make_decl_rtl$stub
        jmp     LBB1_62 ## bb77


after:

        jne     LBB1_63 ## bb79
LBB1_62:        ## bb78
        movl    $0, 4(%esp)
        movl    %esi, (%esp)
        call    L_make_decl_rtl$stub
LBB1_63:        ## bb79
        movl    84(%esi), %eax

The input code was (and the GEPs are merged and
the PHI is now eliminated by instcombine):

        br i1 %tmp233, label %bb78, label %bb77
bb77:           
        %tmp234 = getelementptr %struct.tree_node* %t_addr.3, i32 0, i32 0, i32 22              
        br label %bb79
bb78:           
        call void @make_decl_rtl(%struct.tree_node* %t_addr.3, i8* null) nounwind
        %tmp235 = getelementptr %struct.tree_node* %t_addr.3, i32 0, i32 0, i32 22              
        br label %bb79
bb79:           
        %iftmp.12.0.in = phi %struct.rtx_def** [ %tmp235, %bb78 ], [ %tmp234, %bb77 ]           
        %iftmp.12.0 = load %struct.rtx_def** %iftmp.12.0.in             

llvm-svn: 60322
2008-12-01 02:34:36 +00:00
Bill Wendling 5b902c5b1e Implement ((A|B)&1)|(B&-2) -> (A&1) | B transformation. This also takes care of
permutations of this pattern.

llvm-svn: 60312
2008-12-01 01:07:11 +00:00
Bill Wendling de89bc275c Add instruction combining for ((A&~B)|(~A&B)) -> A^B and all permutations.
llvm-svn: 60291
2008-11-30 13:52:49 +00:00
Bill Wendling 9eef421e12 Implement (A&((~A)|B)) -> A&B transformation in the instruction combiner. This
takes care of all permutations of this pattern.

llvm-svn: 60290
2008-11-30 13:08:13 +00:00
Bill Wendling 2d2e7861b5 getSExtValue() doesn't work for ConstantInts with bitwidth > 64 bits. Use all
APInt calls instead.

This fixes PR3144.

llvm-svn: 60288
2008-11-30 12:38:24 +00:00
Bill Wendling 361c0e5f9c Strengthen check for div inst-combining.
llvm-svn: 60276
2008-11-30 04:33:53 +00:00
Bill Wendling 70635adea3 Instcombine was illegally transforming -X/C into X/-C when either X or C
overflowed on negation. This commit checks to make sure that neithe C nor X
overflows. This requires that the RHS of X (a subtract instruction) be a
constant integer.

llvm-svn: 60275
2008-11-30 03:42:12 +00:00
Nick Lewycky 4ab50b93c8 Chris prefers icmp/select over udiv!
llvm-svn: 60187
2008-11-27 22:41:10 +00:00
Nick Lewycky 69941fd0a0 Add a couple of missed optimizations on integer vectors. Multiply and divide
by 1, as well as multiply by -1.

llvm-svn: 60182
2008-11-27 20:21:08 +00:00
Nick Lewycky 07d726ec4d Optimize (x/y)*y into x-(x%y) in general. Div and rem are about the same, and
a subtract is cheaper than a multiply. This generalizes an existing transform.

llvm-svn: 59800
2008-11-21 07:33:58 +00:00
Chris Lattner c3f3b059d0 Handle the case where there is no "not". It is possible it got
folded into the select.

llvm-svn: 59389
2008-11-16 04:25:26 +00:00
Chris Lattner 645f60141b make this actually test what it is trying to.
llvm-svn: 59386
2008-11-16 04:21:51 +00:00
Bill Wendling 3f547be28f If the LHS of the FCMP is coming from a UIToFP instruction, then we don't want
to generate signed ICMP instructions to replace the FCMP. This would violate
the following:

define i1 @test1(i32 %val) {
  %1 = uitofp i32 %val to double
  %2 = fcmp ole double %1, 0.000000e+00
  ret i1 %2
}

would be transformed into:

define i1 @test1(i32 %val) {
  %1 = icmp slt i33 %val, 1
  ret i1 %1
}

which is obviously wrong. This patch modifes InstCombiner::FoldFCmp_IntToFP_Cst
to handle when the LHS comes from UIToFP.

llvm-svn: 58929
2008-11-09 04:26:50 +00:00
Nick Lewycky 8d8acf327b Fix demanded bits analysis with srem by negative number. Based on a patch
by Richard Osborne.

llvm-svn: 58555
2008-11-02 02:41:50 +00:00
Dan Gohman 83eea0b17f Fix this recently moved code to use the correct type. CI is now a
ConstantInt, and SI is the original cast instruction. This fixes
PR2996.

llvm-svn: 58549
2008-11-02 00:17:33 +00:00
Dan Gohman 13cbcf1c18 Canonicalize sext(i1) to i1?-1:0, and update various instcombine
optimizations accordingly.

llvm-svn: 58457
2008-10-30 20:40:10 +00:00
Dan Gohman 2c34c130bf (A & sext(C)) | (B & ~sext(C) -> C ? A : B
llvm-svn: 58351
2008-10-28 22:38:57 +00:00
Nick Lewycky 730d5dade6 Don't try to create a mask when we don't need one. Fixes a crash.
llvm-svn: 58075
2008-10-24 06:14:27 +00:00
Dan Gohman bc0278400c Teach instcombine's visitLoad to scan back several instructions
to find opportunities for store-to-load forwarding or load CSE,
in the same way that visitStore scans back to do DSE. Also, define
a new helper function for testing whether the addresses of two
memory accesses are known to have the same value, and use it in
both visitStore and visitLoad.

These two changes allow instcombine to eliminate loads in code
produced by front-ends that frequently emit obviously redundant
addressing for memory references.

llvm-svn: 57608
2008-10-15 23:19:35 +00:00
Evan Cheng d885f6e139 Combine (fcmp cc0 x, y) | (fcmp cc1 x, y) into a single fcmp when possible.
llvm-svn: 57515
2008-10-14 18:44:08 +00:00
Evan Cheng ce70752b11 - Somehow I forgot about one / une.
- Renumber fcmp predicates to match their icmp counterparts.
- Try swapping operands to expose more optimization opportunities.

llvm-svn: 57513
2008-10-14 18:13:38 +00:00
Evan Cheng 67786cce66 Optimize anding of two fcmp into a single fcmp if the operands are the same. e.g. uno && ueq -> ueq
ord && olt -> olt
     ord && ueq -> oeq

llvm-svn: 57507
2008-10-14 17:15:11 +00:00
Chris Lattner da435910e8 Fix PR2697 by rewriting the '(X / pos) op neg' logic. This also changes
a couple other cases for clarity, but shouldn't affect correctness.

Patch by Eli Friedman!

llvm-svn: 57387
2008-10-11 22:55:00 +00:00
Chris Lattner 917a6c1343 rewrite bswap matching to be more general, allowing arbitrary
shifting and masking inside a bswap expr.  This allows it to handle
the cases from PR2842, which involve the intermediate 'or' 
expressions being shifted, not just the input value.

llvm-svn: 57095
2008-10-05 02:13:19 +00:00
Nick Lewycky e8ced3ec19 Fix misoptimization of: xor i1 (icmp eq (X, C1), icmp s[lg]t (X, C2))
llvm-svn: 56834
2008-09-30 06:08:34 +00:00
Dan Gohman dafa9c6e85 Improve instcombine's handling of integer min and max in two ways:
- Recognize expressions like "x > -1 ? x : 0" as min/max and turn them
   into expressions like "x < 0 ? 0 : x", which is easily recognizable
   as a min/max operation.
 - Refrain from folding expression like "y/2 < 1" to "y < 2" when the
   comparison is being used as part of a min or max idiom, like
   "y/2 < 1 ? 1 : y/2". In that case, the division has another use, so
   folding doesn't eliminate it, and obfuscates the min/max, making it
   harder to recognize as a min/max operation.

These benefit ScalarEvolution, CodeGen, and anything else that wants to
recognize integer min and max.

llvm-svn: 56246
2008-09-16 18:46:06 +00:00
Dan Gohman eff71f2953 On 64-bit targets, change 32-bit getelementptr indices to be 64-bit
getelementptr indices, inserting an explicit cast if necessary.
This helps expose the sign-extension operation to other optimizations.

llvm-svn: 56133
2008-09-11 23:06:38 +00:00