Commit Graph

1213 Commits

Author SHA1 Message Date
Nick Lewycky
bf433e5f46 Tweak this test. We can analyze what happens and show that we still do the
right thing, instead of merely being unable to analyze and the transform
doesn't occur.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127149 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-07 02:10:18 +00:00
Nick Lewycky
c14bc77315 Add more analysis of the sign bit of an srem instruction. If the LHS is negative
then the result could go either way. If it's provably positive then so is the
srem. Fixes PR9343 #7!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127146 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-07 01:50:10 +00:00
Nick Lewycky
d01f50f42c ConstantInt has some getters which return ConstantInt's or ConstantVector's of
the value splatted into every element. Extend this to getTrue and getFalse which
by providing new overloads that take Types that are either i1 or <N x i1>. Use
it in InstCombine to add vector support to some code, fixing PR8469!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127116 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-06 03:36:19 +00:00
Nick Lewycky
58bfcdbcf6 Thread comparisons over udiv/sdiv/ashr/lshr exact and lshr nuw/nsw whenever
possible. This goes into instcombine and instsimplify because instsimplify
doesn't need to check hasOneUse since it returns (almost exclusively) constants.

This fixes PR9343 #4 #5 and #8!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127064 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 05:19:11 +00:00
Nick Lewycky
9feda1730c Try once again to optimize "icmp (srem X, Y), Y" by turning the comparison into
true/false or "icmp slt/sge Y, 0".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127063 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 04:28:48 +00:00
Nick Lewycky
786792784e Fold "icmp pred (srem X, Y), Y" like we do for urem. Handle signed comparisons
in the urem case, though not the other way around. This is enough to get #3 from
PR9343!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126991 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04 10:06:52 +00:00
Anders Carlsson
d70be0b2c1 Make InstCombiner::FoldAndOfICmps create a ConstantRange that's the
intersection of the LHS and RHS ConstantRanges and return "false" when
the range is empty.

This simplifies some code and catches some extra cases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126744 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01 15:05:01 +00:00
Nick Lewycky
3dc7e49c70 srem doesn't actually have the same resulting sign as its numerator, you could
also have a zero when numerator = denominator. Reverts parts of r126635 and
r126637.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126644 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-28 09:17:39 +00:00
Nick Lewycky
b042f8e969 Teach InstCombine to fold "(shr exact X, Y) == 0" --> X == 0, fixing #1 from
PR9343.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126643 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-28 08:31:40 +00:00
Nick Lewycky
d8d1584c13 The sign of an srem instruction is the sign of its dividend (the first
argument), regardless of the divisor. Teach instcombine about this and fix
test7 in PR9343!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126635 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-28 06:20:05 +00:00
Chris Lattner
091b1e3c74 change instcombine to not turn a call to non-varargs bitcast of
function prototype into a call to a varargs prototype.  We do
allow the xform if we have a definition, but otherwise we don't
want to risk that we're changing the abi in a subtle way.  On
X86-64, for example, varargs require passing stuff in %al.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126363 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-24 05:10:56 +00:00
Benjamin Kramer
91e37ef278 InstCombine: Add a bunch of combines of the form x | (y ^ z).
We usually catch this kind of optimization through InstSimplify's distributive
magic, but or doesn't distribute over xor in general.

"A | ~(A | B) -> A | ~B" hits 24 times on gcc.c.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126081 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-20 13:23:43 +00:00
Eli Friedman
1347623aaf PR9218: SimplifyDemandedVectorElts can return a non-null value that is not
the instruction passed in.  Make sure to account for this correctly, instead
of looping infinitely.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126058 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19 22:42:40 +00:00
Duncan Sands
39a7de72c8 Add some transforms of the kind X-Y>X -> 0>Y which are valid when there is no
overflow.  These subsume some existing equality transforms, so zap those.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125843 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-18 16:25:37 +00:00
Chris Lattner
c8cb8ef9c2 have instcombine preserve nsw/nuw/exact when sinking
common operations through a phi. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125790 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 23:01:49 +00:00
Chris Lattner
4bd8217af3 fix instcombine merging GEPs through a PHI to only make the
result inbounds if all of the inputs are inbounds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125785 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 22:21:26 +00:00
Nadav Rotem
093399cbf3 Enhance constant folding of bitcast operations on vectors of floats.
Add getAllOnesValue of FP numbers to Constants and APFloat.
Add more tests.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125776 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 21:22:27 +00:00
Duncan Sands
a77243300b Transform "A + B >= A + C" into "B >= C" if the adds do not wrap. Likewise for some
variations (some of these were already present so I unified the code).  Spotted by my
auto-simplifier as occurring a lot.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125734 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 07:46:37 +00:00
Chris Lattner
41429e3f1e preserve NUW/NSW when transforming add x,x
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125711 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 02:23:02 +00:00
Chris Lattner
3e468e1efa filecheckize
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125710 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 02:21:03 +00:00
Nick Lewycky
8a670edf1b Teach PatternMatch that splat vectors could be floating point as well as
integer. Fixes PR9228!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125613 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 23:13:23 +00:00
Nadav Rotem
d9e087bbc3 Fix 9216 - Endless loop in InstCombine pass.
The pattern "A&(A^B) -> A & ~B" recreated itself because ~B is
actually a xor -1.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125557 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-15 07:13:48 +00:00
Nadav Rotem
d239e5af64 Fix test
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125460 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 16:13:16 +00:00
Nadav Rotem
bc53ca1b53 Fix a regression from r125393;
It caused a crash in MultiSource/Benchmarks/Bullet.
Opt hit an assertion with "opt -std-compile-opts" because
Constant::getAllOnesValue doesn't know how to handle floats.

This patch added a test to reproduce the problem and a check that the
destination vector is of integer type.

Thank you Benjamin!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125459 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 15:45:34 +00:00
Chris Lattner
b289b40744 add PR#
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125455 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 08:27:31 +00:00
Chris Lattner
bb75d337c4 implement instcombine folding for things like (x >> c) < 42.
We were previously simplifying divisions, but not right shifts!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125454 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-13 08:07:21 +00:00
Benjamin Kramer
b6c8cb4422 Also fold (A+B) == A -> B == 0 when the add is commuted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125411 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-11 21:46:48 +00:00
Nadav Rotem
d2f27ead2d Fix 9173.
Add more folding patterns to constant expressions of vector selects and vector
bitcasts.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125393 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-11 19:37:55 +00:00
Chris Lattner
6cdf2ea98e implement the first part of PR8882: when lowering an inbounds
gep to explicit addressing, we know that none of the intermediate
computation overflows.

This could use review: it seems that the shifts certainly wouldn't
overflow, but could the intermediate adds overflow if there is a 
negative index?

Previously the testcase would instcombine to:

define i1 @test(i64 %i) {
  %p1.idx.mask = and i64 %i, 4611686018427387903
  %cmp = icmp eq i64 %p1.idx.mask, 1000
  ret i1 %cmp
}

now we get:

define i1 @test(i64 %i) {
  %cmp = icmp eq i64 %i, 1000
  ret i1 %cmp
}



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125271 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 07:11:16 +00:00
Chris Lattner
7a6aa1a391 Enhance a bunch of transformations in instcombine to start generating
exact/nsw/nuw shifts and have instcombine infer them when it can prove
that the relevant properties are true for a given shift without them.

Also, a variety of refactoring to use the new patternmatch logic thrown
in for good luck.  I believe that this takes care of a bunch of related
code quality issues attached to PR8862.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125267 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:36:31 +00:00
Chris Lattner
b20c0b5092 Enhance the "compare with shift" and "compare with div"
optimizations to be much more aggressive in the face of
exact/nsw/nuw div and shifts.  For example, these (which
are the same except the first is 'exact' sdiv:

define i1 @sdiv_icmp4_exact(i64 %X) nounwind {
  %A = sdiv exact i64 %X, -5   ; X/-5 == 0 --> x == 0
  %B = icmp eq i64 %A, 0
  ret i1 %B
}

define i1 @sdiv_icmp4(i64 %X) nounwind {
  %A = sdiv i64 %X, -5   ; X/-5 == 0 --> x == 0
  %B = icmp eq i64 %A, 0
  ret i1 %B
}

compile down to:

define i1 @sdiv_icmp4_exact(i64 %X) nounwind {
  %1 = icmp eq i64 %X, 0
  ret i1 %1
}

define i1 @sdiv_icmp4(i64 %X) nounwind {
  %X.off = add i64 %X, 4
  %1 = icmp ult i64 %X.off, 9
  ret i1 %1
}

This happens when you do something like:
  (ptr1-ptr2) == 42

where the pointers are pointers to non-unit types.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125266 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:23:05 +00:00
Chris Lattner
44cc997d42 more cleanups, notably bitcast isn't used for "signed to unsigned type
conversions". :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125265 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-10 05:17:27 +00:00
Chris Lattner
6bfd77e315 merge two tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125195 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 17:06:41 +00:00
Chris Lattner
35bda8914c enhance vmcore to know that udiv's can be exact, and add a trivial
instcombine xform to exercise this.

Nothing forms exact udivs yet though.  This is progress on PR8862



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124992 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-06 21:44:57 +00:00
Anders Carlsson
77bc49e5e2 Recognize and simplify
(A+B) == A  ->  B == 0
A == (A+B)  ->  B == 0



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124567 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-30 22:01:13 +00:00
Duncan Sands
593faa53fa My auto-simplifier noticed that ((X/Y)*Y)/Y occurs several times in SPEC
benchmarks, and that it can be simplified to X/Y.  (In general you can only
simplify (Z*Y)/Y to Z if the multiplication did not overflow; if Z has the
form "X/Y" then this is the case).  This patch implements that transform and
moves some Div logic out of instcombine and into InstructionSimplify.
Unfortunately instcombine gets in the way somewhat, since it likes to change
(X/Y)*Y into X-(X rem Y), so I had to teach instcombine about this too.
Finally, thanks to the NSW/NUW flags, sometimes we know directly that "Z*Y"
does not overflow, because the flag says so, so I added that logic too.  This
eliminates a bunch of divisions and subtractions in 447.dealII, and has good
effects on some other benchmarks too.  It seems to have quite an effect on
tramp3d-v4 but it's hard to say if it's good or bad because inlining decisions
changed, resulting in massive changes all over.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124487 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 16:51:11 +00:00
Nick Lewycky
26859587fd Clean up the tests a little, make sure we match an instruction in the right
test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124473 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 05:13:17 +00:00
Nick Lewycky
df3bfae151 Fold select + select where both selects are on the same condition.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124469 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28 03:28:10 +00:00
Owen Anderson
5d2e188962 Just because we have determined that an (fcmp | fcmp) is true for A < B,
A == B, and A > B, does not mean we can fold it to true.  We still need to
check for A ? B (A unordered B).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123993 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-21 19:39:42 +00:00
Chris Lattner
cd151d2f95 fix PR9013, an infinite loop in instcombine.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123968 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-21 05:29:50 +00:00
Nick Lewycky
acf4a7c0e6 Don't try to pull vector bitcasts that change the number of elements through
a select. A vector select is pairwise on each element so we'd need a new
condition with the right number of elements to select on. Fixes PR8994.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123963 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-21 02:30:43 +00:00
Chris Lattner
192228edb1 enhance FoldOpIntoPhi in instcombine to try harder when a phi has
multiple uses.  In some cases, all the uses are the same operation,
so instcombine can go ahead and promote the phi.  In the testcase
this pushes an add out of the loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123568 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-16 05:28:59 +00:00
Chris Lattner
156eb0a569 fix PR8983, a broken assertion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123562 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-16 03:43:53 +00:00
Chris Lattner
62fe406dc2 implement an instcombine xform that canonicalizes casts outside of and-with-constant operations.
This fixes rdar://8808586 which observed that we used to compile:


union xy {
        struct x { _Bool b[15]; } x;
        __attribute__((packed))
        struct y {
                __attribute__((packed)) unsigned long b0to7;
                __attribute__((packed)) unsigned int b8to11;
                __attribute__((packed)) unsigned short b12to13;
                __attribute__((packed)) unsigned char b14;
        } y;
};

struct x
foo(union xy *xy)
{
        return xy->x;
}

into:

_foo:                                   ## @foo
	movq	(%rdi), %rax
	movabsq	$1095216660480, %rcx    ## imm = 0xFF00000000
	andq	%rax, %rcx
	movabsq	$-72057594037927936, %rdx ## imm = 0xFF00000000000000
	andq	%rax, %rdx
	movzbl	%al, %esi
	orq	%rdx, %rsi
	movq	%rax, %rdx
	andq	$65280, %rdx            ## imm = 0xFF00
	orq	%rsi, %rdx
	movq	%rax, %rsi
	andq	$16711680, %rsi         ## imm = 0xFF0000
	orq	%rdx, %rsi
	movl	%eax, %edx
	andl	$-16777216, %edx        ## imm = 0xFFFFFFFFFF000000
	orq	%rsi, %rdx
	orq	%rcx, %rdx
	movabsq	$280375465082880, %rcx  ## imm = 0xFF0000000000
	movq	%rax, %rsi
	andq	%rcx, %rsi
	orq	%rdx, %rsi
	movabsq	$71776119061217280, %r8 ## imm = 0xFF000000000000
	andq	%r8, %rax
	orq	%rsi, %rax
	movzwl	12(%rdi), %edx
	movzbl	14(%rdi), %esi
	shlq	$16, %rsi
	orl	%edx, %esi
	movq	%rsi, %r9
	shlq	$32, %r9
	movl	8(%rdi), %edx
	orq	%r9, %rdx
	andq	%rdx, %rcx
	movzbl	%sil, %esi
	shlq	$32, %rsi
	orq	%rcx, %rsi
	movl	%edx, %ecx
	andl	$-16777216, %ecx        ## imm = 0xFFFFFFFFFF000000
	orq	%rsi, %rcx
	movq	%rdx, %rsi
	andq	$16711680, %rsi         ## imm = 0xFF0000
	orq	%rcx, %rsi
	movq	%rdx, %rcx
	andq	$65280, %rcx            ## imm = 0xFF00
	orq	%rsi, %rcx
	movzbl	%dl, %esi
	orq	%rcx, %rsi
	andq	%r8, %rdx
	orq	%rsi, %rdx
	ret

We now compile this into:

_foo:                                   ## @foo
## BB#0:                                ## %entry
	movzwl	12(%rdi), %eax
	movzbl	14(%rdi), %ecx
	shlq	$16, %rcx
	orl	%eax, %ecx
	shlq	$32, %rcx
	movl	8(%rdi), %edx
	orq	%rcx, %rdx
	movq	(%rdi), %rax
	ret

A small improvement :-)



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123520 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-15 06:32:33 +00:00
Duncan Sands
c43cee3fbb Move some shift transforms out of instcombine and into InstructionSimplify.
While there, I noticed that the transform "undef >>a X -> undef" was wrong.
For example if X is 2 then the top two bits must be equal, so the result can
not be anything.  I fixed this in the constant folder as well.  Also, I made
the transform for "X << undef" stronger: it now folds to undef always, even
though X might be zero.  This is in accordance with the LangRef, but I must
admit that it is fairly aggressive.  Also, I added "i32 X << 32 -> undef"
following the LangRef and the constant folder, likewise fairly aggressive.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123417 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14 00:37:45 +00:00
Owen Anderson
da1c122da5 Fix a random missed optimization by making InstCombine more aggressive when determining which bits are demanded by
a comparison against a constant.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123203 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11 00:36:45 +00:00
Chandler Carruth
9cc9f50abc Teach instcombine about the rest of the SSE and SSE2 conversion
intrinsics element dependencies. Reviewed by Nick.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123161 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 07:19:37 +00:00
Chandler Carruth
fdc8f2d260 Fold two related tests into the newly FileCheck-ized test, migrating
them to FileCheck as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123154 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 02:53:58 +00:00
Chandler Carruth
548e581dcb Clean up and FileCheck-ize a test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123153 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 02:53:54 +00:00
Tobias Grosser
aa2be84356 Instcombine: Fix pattern where the sext did not dominate the icmp using it
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123121 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 16:00:11 +00:00