Commit Graph

114 Commits

Author SHA1 Message Date
Chandler Carruth 6665d62117 Fix a somewhat subtle pair of issues with JumpThreading I introduced in
r220178. First, the creation routine doesn't insert prior to the
terminator of the basic block provided, but really at the end of the
basic block. Instead, get the terminator and insert before that. The
next issue was that we need to ensure multiple PHI node entries for
a single predecessor re-use the same cast instruction rather than
creating new ones.

All of the logic here was without tests previously. I've reduced and
added a test case from the test suite that crashed without both of these
fixes.

llvm-svn: 220186
2014-10-20 05:34:36 +00:00
Hal Finkel a3f23e3725 [LVI] Check for @llvm.assume dominating the edge branch
When LazyValueInfo uses @llvm.assume intrinsics to provide edge-value
constraints, we should check for intrinsics that dominate the edge's branch,
not just any potential context instructions. An assumption that dominates the
edge's branch represents a truth on that edge. This is specifically useful, for
example, if multiple predecessors assume a pointer to be nonnull, allowing us
to simplify a later null comparison.

The test case, and an initial patch, were provided by Philip Reames. Thanks!

llvm-svn: 219688
2014-10-14 16:04:49 +00:00
James Molloy cb7449d058 Revert r215343.
This was contentious and needs invesigation.

llvm-svn: 218971
2014-10-03 09:29:24 +00:00
Hal Finkel 7e1844940e Make use of @llvm.assume from LazyValueInfo
This change teaches LazyValueInfo to use the @llvm.assume intrinsic. Like with
the known-bits change (r217342), this requires feeding a "context" instruction
pointer through many functions. Aside from a little refactoring to reuse the
logic that turns predicates into constant ranges in LVI, the only new code is
that which can 'merge' the range from an assumption into that otherwise
computed. There is also a small addition to JumpThreading so that it can have
LVI use assumptions in the same block as the comparison feeding a conditional
branch.

With this patch, we can now simplify this as expected:
int foo(int a) {
  __builtin_assume(a > 5);
  if (a > 3) {
    bar();
    return 1;
  }
  return 0;
}

llvm-svn: 217345
2014-09-07 20:29:59 +00:00
Jiangning Liu 40b04fd994 In LVI(Lazy Value Info), originally value on a BB can only be caculated once,
and the lattice will be updated to be a state other than "undefined". This
limiation could miss some opportunities of lowering "overdefined" to be an
even accurate value. So this patch ask the algorithm to try to lower the
lattice value again even if the value has been lowered to be "overdefined".

llvm-svn: 215343
2014-08-11 05:02:04 +00:00
Dinesh Dwivedi 657105e582 Fixed jump threading going to infinite loop.
This patch add code to remove unreachable blocks from function
as they may cause jump threading to stuck in infinite loop.

Differential Revision: http://reviews.llvm.org/D3991

llvm-svn: 211103
2014-06-17 14:34:19 +00:00
Arnaud A. de Grandmaison de5ff26865 No need for those tests to go thru llvm-as and/or llvm-dis.
opt can handle them by itself.

llvm-svn: 209689
2014-05-27 22:03:28 +00:00
Bill Wendling 90dd90afcb Don't eliminate a partially redundant load if it's in a landing pad.
A landing pad can be jumped to only by the unwind edge of an invoke
instruction. If we eliminate a partially redundant load in a landing pad, it
will create a basic block that violates this constraint. It then leads to other
problems down the line if it tries to merge that basic block with the landing
pad. Avoid this by not eliminating the load in a landing pad.

PR17621

llvm-svn: 193064
2013-10-21 04:09:17 +00:00
Bill Wendling 4fea22c63b Perform an intelligent splice of the predecessor with the single successor.
If the predecessor's being spliced into a landing pad, then we need the PHIs to
come first and the rest of the predecessor's code to come *after* the landing
pad instruction.

llvm-svn: 193035
2013-10-19 11:27:12 +00:00
Manman Ren 0ed04fc9ab TBAA: handle scalar TBAA format and struct-path aware TBAA format.
Remove the command line argument "struct-path-tbaa" since we should not depend
on command line argument to decide which format the IR file is using. Instead,
we check the first operand of the tbaa tag node, if it is a MDNode, we treat
it as struct-path aware TBAA format, otherwise, we treat it as scalar TBAA
format.

When clang starts to use struct-path aware TBAA format no matter whether
struct-path-tbaa is no, and we can auto-upgrade existing bc files, the support
for scalar TBAA format can be dropped.

Existing testing cases are updated to use the struct-path aware TBAA format.

llvm-svn: 191538
2013-09-27 18:34:27 +00:00
Daniel Dunbar 9efbedfd35 [tests] Cleanup initialization of test suffixes.
- Instead of setting the suffixes in a bunch of places, just set one master
   list in the top-level config. We now only modify the suffix list in a few
   suites that have one particular unique suffix (.ml, .mc, .yaml, .td, .py).

 - Aside from removing the need for a bunch of lit.local.cfg files, this enables
   4 tests that were inadvertently being skipped (one in
   Transforms/BranchFolding, a .s file each in DebugInfo/AArch64 and
   CodeGen/PowerPC, and one in CodeGen/SI which is now failing and has been
   XFAILED).

 - This commit also fixes a bunch of config files to use config.root instead of
   older copy-pasted code.

llvm-svn: 188513
2013-08-16 00:37:11 +00:00
Benjamin Kramer 6a4976d3e0 JumpThreading: Turn a select instruction into branching if it allows to thread one half of the select.
This is a common pattern coming out of simplifycfg generating gross code.

a:                                       ; preds = %entry
  %sel = select i1 %cmp1, double %add, double 0.000000e+00
  br label %b

b:
  %cond5 = phi double [ %sel, %a ], [ %sub, %entry ]
  %cmp6 = fcmp oeq double %cond5, 0.000000e+00
  br i1 %cmp6, label %if.then, label %if.end

becomes

a:
  br i1 %cmp1, label %b, label %if.then

b:
  %cond5 = phi double [ %sub, %entry ], [ %add, %a ]
  %cmp6 = fcmp oeq double %cond5, 0.000000e+00
  br i1 %cmp6, label %if.then, label %if.end

Skipping block b completely if possible.

llvm-svn: 187880
2013-08-07 10:29:38 +00:00
Stephen Lin c1c7a1309c Update Transforms tests to use CHECK-LABEL for easier debugging. No functionality change.
This update was done with the following bash script:

  find test/Transforms -name "*.ll" | \
  while read NAME; do
    echo "$NAME"
    if ! grep -q "^; *RUN: *llc" $NAME; then
      TEMP=`mktemp -t temp`
      cp $NAME $TEMP
      sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \
      while read FUNC; do
        sed -i '' "s/;\(.*\)\([A-Za-z0-9_]*\):\( *\)@$FUNC\([( ]*\)\$/;\1\2-LABEL:\3@$FUNC(/g" $TEMP
      done
      mv $TEMP $NAME
    fi
  done

llvm-svn: 186268
2013-07-14 01:42:54 +00:00
Manman Ren 1a5ff287fd TBAA: remove !tbaa from testing cases if not used.
This will make it easier to turn on struct-path aware TBAA since the metadata
format will change.

llvm-svn: 180796
2013-04-30 17:52:57 +00:00
Bill Wendling a032374ea0 Use references to attribute groups on the call/invoke instructions.
Listing all of the attributes for the callee of a call/invoke instruction is way
too much and makes the IR unreadable. Use references to attributes instead.

llvm-svn: 175877
2013-02-22 09:09:42 +00:00
Dmitri Gribenko d7beca87f5 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.

My previous regex was not good enough to find these.

llvm-svn: 171343
2013-01-01 13:57:25 +00:00
Dmitri Gribenko 56bf2e1830 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.

llvm-svn: 171250
2012-12-30 02:33:22 +00:00
Dmitri Gribenko b137c9e551 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.

llvm-svn: 171246
2012-12-30 01:28:40 +00:00
James Molloy 4f6fb953a7 Add a new attribute, 'noduplicate'. If a function contains a noduplicate call, the call cannot be duplicated - Jump threading, loop unrolling, loop unswitching, and loop rotation are inhibited if they would duplicate the call.
Similarly inlining of the function is inhibited, if that would duplicate the call (in particular inlining is still allowed when there is only one callsite and the function has internal linkage).

llvm-svn: 170704
2012-12-20 16:04:27 +00:00
Chandler Carruth d5639ff80f Add a test case for PR14233.
llvm-svn: 167224
2012-11-01 10:26:36 +00:00
Manman Ren f3fedb6935 JumpThreading: when default destination is the destination of some cases in a
switch, make sure we include the value for the cases when calculating edge
value from switch to the default destination.

rdar://12241132

llvm-svn: 163270
2012-09-05 23:45:58 +00:00
Richard Osborne 0ab2b0df82 Fix assertion in jump threading (PR13405).
GetBestDestForJumpOnUndef() assumes there is at least 1 successor, which isn't
true if the block ends in an indirect branch with no successors. Fix this by
bailing out earlier in this case.

llvm-svn: 160546
2012-07-20 10:36:17 +00:00
Chandler Carruth ff123d5c63 Fix the remaining TCL-style quotes found in the testsuite. This is
another mechanical change accomplished though the power of terrible Perl
scripts.

I have manually switched some "s to 's to make escaping simpler.

While I started this to fix tests that aren't run in all configurations,
the massive number of tests is due to a really frustrating fragility of
our testing infrastructure: things like 'grep -v', 'not grep', and
'expected failures' can mask broken tests all too easily.

Essentially, I'm deeply disturbed that I can change the testsuite so
radically without causing any change in results for most platforms. =/

llvm-svn: 159547
2012-07-02 19:09:46 +00:00
Chandler Carruth a5a29f970e Convert all tests using TCL-style quoting to use shell-style quoting.
This was done through the aid of a terrible Perl creation. I will not
paste any of the horrors here. Suffice to say, it require multiple
staged rounds of replacements, state carried between, and a few
nested-construct-parsing hacks that I'm not proud of. It happens, by
luck, to be able to deal with all the TCL-quoting patterns in evidence
in the LLVM test suite.

If anyone is maintaining large out-of-tree test trees, feel free to poke
me and I'll send you the steps I used to convert things, as well as
answer any painful questions etc. IRC works best for this type of thing
I find.

Once converted, switch the LLVM lit config to use ShTests the same as
Clang. In addition to being able to delete large amounts of Python code
from 'lit', this will also simplify the entire test suite and some of
lit's architecture.

Finally, the test suite runs 33% faster on Linux now. ;]
For my 16-hardware-thread (2x 4-core xeon e5520): 36s -> 24s

llvm-svn: 159525
2012-07-02 12:47:22 +00:00
Joel Jones 7f04344b8b formatting change: strip debug info from test
llvm-svn: 156551
2012-05-10 16:55:31 +00:00
Joel Jones 3d90a9ae65 Fix a problem with incomplete equality testing of PHINodes in
Instruction::IsIdenticalToWhenDefined.

This manifested itself when inlining two calls to the same function.  The 
inlined function had a switch statement that returned one of a set of 
global variables.  Without this modification, the two phi instructions that 
chose values from the branches of the switch instruction inlined from the 
callee were considered equivalent and jump-threading replaced a load for the 
first switch value with a phi selecting from the second switch, thereby 
producing incorrect code.

This patch has been tested with "make check-all", "lnt runteste nt", and 
llvm self-hosted, and on the original program that had this problem, 
wireshark.

<rdar://problem/11025519>

llvm-svn: 156548
2012-05-10 15:59:41 +00:00
Chris Lattner 87fa77bd8a enhance jump threading to preserve TBAA information when PRE'ing loads,
fixing rdar://11039258, an issue that came up when inspecting clang's 
bootstrapped codegen.

llvm-svn: 152635
2012-03-13 18:07:41 +00:00
Eli Bendersky 924f9a671d Replace all instances of dg.exp file with lit.local.cfg, since all tests are run with LIT now and now Dejagnu. dg.exp is no longer needed.
Patch reviewed by Daniel Dunbar. It will be followed by additional cleanup patches.

llvm-svn: 150664
2012-02-16 06:28:33 +00:00
Chris Lattner 6a144a2227 Upgrade syntax of tests using volatile instructions to use 'load volatile' instead of 'volatile load', which is archaic.
llvm-svn: 145171
2011-11-27 06:54:59 +00:00
Eli Friedman 02e737b08e Move "atomic" and "volatile" designations on instructions after the opcode
of the instruction.

Note that this change affects the existing non-atomic load and store
instructions; the parser now accepts both forms, and the change is noted
in the release notes.

llvm-svn: 137527
2011-08-12 22:50:01 +00:00
Chris Lattner 59345c8b65 remove asmparser support for the old getresult instruction, which has been subsumed by extractvalue.
llvm-svn: 133247
2011-06-17 06:57:15 +00:00
Owen Anderson 92651ec374 Fix an infinite alternation in JumpThreading where two transforms would repeatedly undo each other. The solution is to perform more aggressive constant folding to make one of the edges just folded away rather than trying to thread it.
Fixes <rdar://problem/9284786>.

Discovered with CSmith.

llvm-svn: 129538
2011-04-14 21:35:50 +00:00
Eli Friedman 17bf4922c9 PR9446: RecursivelyDeleteTriviallyDeadInstructions can delete the instruction
after the given instruction; make sure to handle that case correctly.
(It's difficult to trigger; the included testcase involves a dead 
block, but I don't think that's a requirement.) 

While I'm here, get rid of the unnecessary warning about
SimplifyInstructionsInBlock, since it should work correctly as far as I know.

llvm-svn: 128782
2011-04-02 22:45:17 +00:00
Duncan Sands 7dc3d47c34 Fix PR9331. Simplified version of a patch by Jakub Staszak.
llvm-svn: 127243
2011-03-08 12:39:03 +00:00
Chris Lattner 1a924e770a prevent jump threading from merging blocks when their address is
taken (and used!).  This prevents merging the blocks (invalidating
the block addresses) in a case like this:

#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })

void foo() {
  printf("%p\n", _THIS_IP_);
  printf("%p\n", _THIS_IP_);
  printf("%p\n", _THIS_IP_);
}

which fixes PR4151.

llvm-svn: 125829
2011-02-18 04:43:06 +00:00
Nick Lewycky ac0b62c277 Tolerate degenerate phi nodes that can occur in the middle of optimization
passes. Fixes PR9112. Patch by Jakub Staszak!

llvm-svn: 125319
2011-02-10 23:54:10 +00:00
Evan Cheng d983eba7dc Re-apply r124518 with fix. Watch out for invalidated iterator.
llvm-svn: 124526
2011-01-29 04:46:23 +00:00
Evan Cheng 65b8ccf6ac Revert r124518. It broke Linux self-host.
llvm-svn: 124522
2011-01-29 02:43:04 +00:00
Evan Cheng d4eff31476 Re-commit r124462 with fixes. Tail recursion elim will now dup ret into unconditional predecessor to enable TCE on demand.
llvm-svn: 124518
2011-01-29 01:29:26 +00:00
Evan Cheng aaa9606b2f Revert r124462. There are a few big regressions that I need to fix first.
llvm-svn: 124478
2011-01-28 07:12:38 +00:00
Evan Cheng 417fca86c4 - Stop simplifycfg from duplicating "ret" instructions into unconditional
branches. PR8575, rdar://5134905, rdar://8911460.
- Allow codegen tail duplication to dup small return blocks after register
  allocation is done.

llvm-svn: 124462
2011-01-28 02:19:21 +00:00
Frits van Bommel 3d1803495e Teach jump threading to "look through" a select when the branch direction of a terminator depends on it.
When it sees a promising select it now tries to figure out whether the condition of the select is known in any of the predecessors and if so it maps the operands appropriately.

llvm-svn: 121859
2010-12-15 09:51:20 +00:00
Frits van Bommel d9df6eaa9c Implement jump threading of 'indirectbr' by keeping track of whether we're looking for ConstantInt*s or BlockAddress*s.
llvm-svn: 121066
2010-12-06 23:36:56 +00:00
Owen Anderson 99c985c37d Fix PR8247: JumpThreading can cause a block to become unreachable while still having predecessor, if it is part of a self-loop.
Because of this, we cannot use the Simplify* APIs, as they can assert-fail on unreachable code.  Since it's not easy to determine
if a given threading will cause a block to become unreachable, simply defer simplifying simplification to later InstCombine and/or
DCE passes.

llvm-svn: 115082
2010-09-29 20:34:41 +00:00
Owen Anderson f6fe577e88 Remove dead option from tests.
llvm-svn: 113855
2010-09-14 21:03:40 +00:00
Owen Anderson a5e6b3eca4 Merge 2010-08-31-InfiniteRecursion.ll into crash.ll.
llvm-svn: 112635
2010-08-31 20:27:17 +00:00
Owen Anderson 799a08ae48 Add a test for the duplicated-conditional situation illutrated by PR5652.
llvm-svn: 112621
2010-08-31 18:49:12 +00:00
Owen Anderson 3931c85956 Manually reduce this testcase.
llvm-svn: 112615
2010-08-31 18:16:29 +00:00
Owen Anderson ada0623725 Add a micro-test for the transforms I added to JumpThreading.
I have not been able to find a way to test each in isolation, for a few reasons:
1) The ability to look-through non-i1 BinaryOperator's requires the ability to look through non-constant
   ICmps in order for it to ever trigger.
2) The ability to do LVI-powered PHI value determination only matters in cases that ProcessBranchOnPHI
   can't handle.  Since it already handles all the cases without other instructions in the def-use chain
   between the PHI and the branch, it requires the ability to look through ICmps and/or BinaryOperators
   as well.

llvm-svn: 112611
2010-08-31 17:59:07 +00:00
Owen Anderson 3997a07fb9 More Chris-inspired JumpThreading fixes: use ConstantExpr to correctly constant-fold undef, and be more careful with its return value.
This actually exposed an infinite recursion bug in ComputeValueKnownInPredecessors which theoretically already existed (in JumpThreading's
handling of and/or of i1's), but never manifested before.  This patch adds a tracking set to prevent this case.

llvm-svn: 112589
2010-08-31 07:36:34 +00:00