Commit Graph

974 Commits

Author SHA1 Message Date
Dan Gohman
d76d71a291 Factor the code for collecting IV users out of LSR into an IVUsers class,
and generalize it so that it can be used by IndVarSimplify. Implement the
base IndVarSimplify transformation code using IVUsers. This removes
TestOrigIVForWrap and associated code, as ScalarEvolution now has enough
builtin overflow detection and folding logic to handle all the same cases,
and more. Run "opt -iv-users -analyze -disable-output" on your favorite
loop for an example of what IVUsers does.

This lets IndVarSimplify eliminate IV casts and compute trip counts in
more cases. Also, this happens to finally fix the remaining testcases
in PR1301.

Now that IndVarSimplify is being more aggressive, it occasionally runs
into the problem where ScalarEvolutionExpander's code for avoiding
duplicate expansions makes it difficult to ensure that all expanded
instructions dominate all the instructions that will use them. As a
temporary measure, IndVarSimplify now uses a FixUsesBeforeDefs function
to fix up instructions inserted by SCEVExpander. Fortunately, this code
is contained, and can be easily removed once a more comprehensive
solution is available.

llvm-svn: 71535
2009-05-12 02:17:14 +00:00
Dan Gohman
ae451600fa When forgetting SCEVs for loop PHIs, don't forget SCEVUnknown values.
These values aren't analyzable, so they don't care if more information
about the loop trip count can be had. Also, SCEVUnknown is used for
a PHI while the PHI itself is being analyzed, so it needs to be left
in the Scalars map. This fixes a variety of subtle issues.

llvm-svn: 71533
2009-05-12 01:27:58 +00:00
Chris Lattner
c48091f141 fix RewriteStoreUserOfWholeAlloca to use the correct type size
method, fixing a crash on PR4146.  While the store will 
ultimately overwrite the "padded size" number of bits in memory,
the stored value may be a subset of this size.  This function
only wants to handle the case where all bits are stored.

llvm-svn: 71224
2009-05-08 15:54:41 +00:00
Eli Friedman
36b9026fa7 PR4123: don't crash when inlining a call which uses its own result.
llvm-svn: 71199
2009-05-08 00:22:04 +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
Duncan Sands
7a8cfafd2e Revert r70876 and add a testcase (@c7) showing the problem:
bits captured, but the pointer marked nocapture.  In fact
I now recall that this problem is why only readnone functions
returning void were considered before!  However keep a small
fix that was also in r70876: a readnone function returning
void can result in bits being captured if it unwinds, so
test for this.

llvm-svn: 71168
2009-05-07 18:08:34 +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
Duncan Sands
9759f2e063 Fix PR3754: don't mark functions that wrap MallocInst with
the readnone.  Since MallocInst is scheduled for deletion
it doesn't seem worth doing anything more subtle, such as
having mayWriteToMemory return true for MallocInst.

llvm-svn: 71077
2009-05-06 08:42:00 +00:00
Duncan Sands
1efabaaa2a Allow readonly functions to unwind exceptions. Teach
the optimizers about this.  For example, a readonly
function with no uses cannot be removed unless it is
also marked nounwind.

llvm-svn: 71071
2009-05-06 06:49:50 +00:00
Bill Wendling
5e2ac0cd9c Temporarily reverting r71008. It was causing this failure:
Running /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.src/test/
CodeGen/X86/dg.exp ...
FAIL: /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvm.src/test/
CodeGen/X86/change-compare-stride-1.ll
Failed with exit(1) at line 2
while running: grep {cmpq       $-478,} change-compare-stride-1.ll.tmp
child process exited abnormally

llvm-svn: 71013
2009-05-05 20:49:46 +00:00
David Greene
246a3dfb10 Handle overflow of 64-bit loop conditions.
llvm-svn: 71008
2009-05-05 20:22:36 +00:00
Duncan Sands
50c70336b0 Teach capture tracking that readonly functions can
only capture their arguments by returning them or
throwing an exception or not based on the argument
value.  Patch essentially by Frits van Bommel.

llvm-svn: 70876
2009-05-04 16:50:29 +00:00
Chris Lattner
d579cb1167 * Sink 4 duplicates of edge threading validity checks and DOUT prints into
ThreadEdge directly.  This shares the code, but is just a refactoring.
* Make JumpThreading compute the set of loop headers and avoid threading
  across them.  This prevents jump threading from forming irreducible 
  loops (goodness) but also prevents it from threading in other cases that
  are beneficial (see the comment above FindFunctionBackedges).

llvm-svn: 70820
2009-05-04 02:28:08 +00:00
Dan Gohman
ff08995589 Previously, RecursivelyDeleteDeadInstructions provided an option
of returning a list of pointers to Values that are deleted. This was
unsafe, because the pointers in the list are, by nature of what
RecursivelyDeleteDeadInstructions does, always dangling. Replace this
with a simple callback mechanism. This may eventually be removed if
all clients can reasonably be expected to use CallbackVH.

Use this to factor out the dead-phi-cycle-elimination code from LSR
utility function, and generalize it to use the
RecursivelyDeleteTriviallyDeadInstructions utility function.

This makes LSR more aggressive about eliminating dead PHI cycles;
adjust tests to either be less trivial or to simply expect fewer
instructions.

llvm-svn: 70636
2009-05-02 18:29:22 +00:00
Dan Gohman
4bafc42185 Don't try to mix integers and pointers in an icmp instruction
in getSCEVAtScope.

llvm-svn: 70495
2009-04-30 16:40:30 +00:00
Dale Johannesen
b0bc5c2f81 Fix recent regression in gcc.dg/pr26719.c (6835035).
llvm-svn: 70386
2009-04-29 16:38:47 +00:00
Dan Gohman
ed7f3a0eec As with r70333, give the primary induction variable a use so
that it can't be trivially eliminated.

llvm-svn: 70334
2009-04-28 22:05:13 +00:00
Dan Gohman
2625f2cb80 Make this testcase slightly less trivial, so that it doesn't fail
if indvars happens to optimize away the unused primary induction
variable.

llvm-svn: 70333
2009-04-28 22:03:26 +00:00
Dale Johannesen
27b4f222cf Fix PR 4086, a bug in FP IV elimination.
llvm-svn: 70247
2009-04-27 21:03:15 +00:00
Dan Gohman
7646637379 Teach getZeroExtendExpr and getSignExtendExpr to use trip-count
information to simplify [sz]ext({a,+,b}) to {zext(a),+,[zs]ext(b)},
as appropriate.

These functions and the trip count code each call into the other, so
this requires careful handling to avoid infinite recursion. During
the initial trip count computation, conservative SCEVs are used,
which are subsequently discarded once the trip count is actually
known.

Among other benefits, this change lets LSR automatically eliminate
some unnecessary zext-inreg and sext-inreg operation where the
operand is an induction variable.

llvm-svn: 70241
2009-04-27 20:16:15 +00:00
Dan Gohman
05c1d372b7 Handle ands with ~0 correctly too. This fixes PR4052.
llvm-svn: 70176
2009-04-27 01:41:10 +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
Dan Gohman
df19948ea7 Handle ands with 0 and shifts by 0 correctly. These aren't
common, but indvars shouldn't crash on them. This fixes PR4054.

llvm-svn: 70051
2009-04-25 17:05:40 +00:00
Dan Gohman
d6f9713634 Fix an error in this test.
llvm-svn: 69893
2009-04-23 15:22:28 +00:00
Dan Gohman
86bcd97014 Change SCEVExpander's expandCodeFor to provide more flexibility
with the persistent insertion point, and change IndVars to make
use of it. This fixes a bug where IndVars was holding on to a
stale insertion point and forcing the SCEVExpander to continue to
use it.

This fixes PR4038.

llvm-svn: 69892
2009-04-23 15:16:49 +00:00
Owen Anderson
b94ea3ebf1 Testcase for PR2639.
llvm-svn: 69867
2009-04-23 04:30:52 +00:00
Owen Anderson
b211b5c478 Testcase for PR2537.
llvm-svn: 69866
2009-04-23 04:26:42 +00:00
Owen Anderson
437c6357e0 Fix typo.
llvm-svn: 69865
2009-04-23 04:24:19 +00:00
Owen Anderson
0e357e5fd3 Testcase for PR3085.
llvm-svn: 69863
2009-04-23 04:21:14 +00:00
Owen Anderson
7e96d34f2e Add testcase from PR3086.
llvm-svn: 69862
2009-04-23 04:14:03 +00:00
Evan Cheng
d8174d3d09 Make sure both operands have binary instructions have the same type.
llvm-svn: 69844
2009-04-22 23:39:28 +00:00
Evan Cheng
cbfe9df096 Avoid deferencing use_begin() if value does not have a use.
llvm-svn: 69836
2009-04-22 22:45:37 +00:00
Dan Gohman
54fd2869a3 SCEVExpander's InsertCastOfTo knows how to move existing cast
instructions in order to avoid inserting new ones. However, if
the cast instruction is the SCEVExpander's InsertPt, this
causes subsequently emitted instructions to be inserted near
the cast, and not at the location of the original insert point.
Fix this by adjusting the insert point in such cases.
This fixes PR4009.

llvm-svn: 69808
2009-04-22 16:11:16 +00:00
Chris Lattner
69223bb7f5 fix a crash on a pointless but valid zero-length memset, rdar://6808691
llvm-svn: 69680
2009-04-21 16:52:12 +00:00
Dale Johannesen
8958f4f30f Another testcase for IV shortening.
llvm-svn: 69247
2009-04-16 00:45:21 +00:00
Dale Johannesen
7ffb7d5728 Enhance induction variable code to remove the
sext around sext(shorter IV + constant), using a
longer IV instead, when it can figure out the
add can't overflow.  This comes up a lot in
subscripting; mainly affects 64 bit.

llvm-svn: 69123
2009-04-15 01:10:12 +00:00
Devang Patel
046bf624b9 While inlining, clone llvm.dbg.func.start intrinsic and adjust
llvm.dbg.region.end instrinsic. This nested llvm.dbg.func.start/llvm.dbg.region.end pair now enables DW_TAG_inlined_subroutine support in code generator.

llvm-svn: 69118
2009-04-15 00:17:06 +00:00
Evan Cheng
5ebf2acd84 Optimize conditional branch on i1 phis with non-constant inputs.
This turns:

eq:
        %3 = icmp eq i32 %1, %2
        br label %join

ne:
        %4 = icmp ne i32 %1, %2
        br label %join

join:
        %5 = phi i1 [%3, %eq], [%4, %ne]
        br i1 %5, label %yes, label %no

=>

eq:
        %3 = icmp eq i32 %1, %2
        br i1 %3, label %yes, label %no

ne:
        %4 = icmp ne i32 %1, %2
        br i1 %4, label %yes, label %no

llvm-svn: 69102
2009-04-14 23:40:03 +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
91b6af24ac add some optimizations for strncpy/strncat and factor some
code.  Patch by Benjamin Kramer!

llvm-svn: 68885
2009-04-12 05:06:39 +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
Ed Schouten
01aa6ec97a Let the strcat optimizer return the pointer to the start of the buffer,
instead of the place where it started to perform the string copy.

- PR3661
- Patch by Benjamin Kramer!

llvm-svn: 68443
2009-04-06 13:06:48 +00:00
Owen Anderson
98f912bf13 Reapply r68211, with the miscompilations it caused fixed.
llvm-svn: 68262
2009-04-01 23:53:49 +00:00
Dan Gohman
c4971721ea Revert r68172. It caused regressions in
Applications/Burg/burg
  Applications/ClamAV/clamscan
and many other tests.

llvm-svn: 68211
2009-04-01 16:37:47 +00:00
Owen Anderson
ff5961b46c Enhance GVN to propagate simple conditionals. This fixes PR3921.
llvm-svn: 68172
2009-04-01 01:20:45 +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
Devang Patel
6e68bd007a Loop Index Split can eliminate a loop if it can determin if loop body is executed only once. There was a bug in determining IV based value of the iteration for which the loop body is executed. Fix it.
llvm-svn: 68071
2009-03-30 22:24:10 +00:00
Devang Patel
4555618854 Before deleting a basic block, give other loop passes a chance cleanup analysis values, related to the instructions in the basic block.
llvm-svn: 67719
2009-03-25 23:57:48 +00:00