Dan Gohman
dd35df15a2
Revert r56315. When the instruction to speculate is a load, this
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code can incorrectly move the load across a store. This never
happens in practice today, but only because the current
heuristics accidentally preclude it.
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2012-01-05 22:54:35 +00:00
Nick Lewycky
8da7ddf2d2
Demystify this comment.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147307 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-28 06:57:32 +00:00
Nick Lewycky
91968489d7
Use false not zero, as a bool.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147292 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-27 18:27:22 +00:00
Nick Lewycky
06cc66f65a
Teach simplifycfg to recompute branch weights when merging some branches, and
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to discard weights when appropriate. Still more to do (and a new TODO), but
it's a start!
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2011-12-27 04:31:52 +00:00
Nick Lewycky
c9a1aed7fe
Update the branch weight metadata when reversing the order of a branch.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147280 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-26 20:54:14 +00:00
Nick Lewycky
9d52310222
Sort includes, canonicalize whitespace, fix typos. No functionality change.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147279 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-26 20:37:40 +00:00
Nick Lewycky
8369687576
Make some intrinsics safe to speculatively execute.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147036 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-21 05:52:02 +00:00
Kevin Enderby
67005b311c
Revert r146822 at Pete Cooper's request as it broke clang self hosting.
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Hope I did this correctly :)
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2011-12-17 19:48:52 +00:00
Pete Cooper
93ca12299f
SimplifyCFG now predicts some conditional branches to true or false depending on previous branch on same comparison operands.
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For example,
if (a == b) {
if (a > b) // this is false
Fixes some of the issues on <rdar://problem/10554090>
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2011-12-17 06:32:38 +00:00
Dan Gohman
f042660197
Move Instruction::isSafeToSpeculativelyExecute out of VMCore and
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into Analysis as a standalone function, since there's no need for
it to be in VMCore. Also, update it to use isKnownNonZero and
other goodies available in Analysis, making it more precise,
enabling more aggressive optimization.
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2011-12-14 23:49:11 +00:00
Duncan Sands
ad99ef8bf5
Delete trivial landing pads that just continue unwinding the caught
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exception.
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2011-09-05 12:57:57 +00:00
Benjamin Kramer
9bb5488dbd
Address review comments.
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- Reword comments.
- Allow undefined behavior interfering with undefined behavior.
- Add address space checks.
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2011-08-26 02:25:55 +00:00
Benjamin Kramer
98d6d2372f
SimplifyCFG: If we have a PHI node that can evaluate to NULL and do a load or store to the address returned by the PHI node then we can consider this incoming value as dead and remove the edge pointing there, unless there are instructions that can affect control flow executed in between.
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In theory this could be extended to other instructions, eg. division by zero, but it's likely that it will "miscompile" some code because people depend on div by zero not trapping. NULL pointer dereference usually leads to a crash so we should be on the safe side.
This shrinks the size of a Release clang by 16k on x86_64.
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2011-08-26 01:22:29 +00:00
Bill Wendling
23b49ba6d5
I think there was some confusion about what I meant. :-) Replacing the comment.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137743 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-16 20:41:17 +00:00
Eli Friedman
6437f2c2e2
After talking with Bill, it seems like the LandingPad handling here is likely
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to be wrong (or at least somewhat suspect). Leave a FIXME for Bill.
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2011-08-16 00:41:37 +00:00
Eli Friedman
33cb445fb6
Minor comment fixes.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137693 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-16 00:20:11 +00:00
Eli Friedman
8176388d65
Update SimplifyCFG for atomic operations.
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This commit includes a mention of the landingpad instruction, but it's not
changing the behavior around it. I think the current behavior is correct,
though. Bill, can you double-check that?
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2011-08-15 23:59:28 +00:00
Chris Lattner
db125cfaf5
land David Blaikie's patch to de-constify Type, with a few tweaks.
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2011-07-18 04:54:35 +00:00
Jay Foad
a3efbb15dd
Convert CallInst and InvokeInst APIs to use ArrayRef.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135265 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-15 08:37:34 +00:00
Rafael Espindola
77a2c372fa
Add r134057 back, but splice the predecessor after the successors phi
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nodes.
Original message:
Let simplify cfg simplify bb with only debug and lifetime intrinsics.
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2011-06-30 20:14:24 +00:00
Chad Rosier
ce77aa3edc
Temporarily revert r134057: "Let simplify cfg simplify bb with only debug and
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lifetime intrinsics" due to buildbot failures.
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2011-06-29 16:22:11 +00:00
Rafael Espindola
0fb7dcd48f
Let simplify cfg simplify bb with only debug and lifetime intrinsics.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134057 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-29 05:25:47 +00:00
Hans Wennborg
448da519cc
Fix PR10103: Less code for enum type translation.
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In cases such as the attached test, where the case value for a switch
destination is used in a phi node that follows the destination, it
might be better to replace that value with the condition value of the
switch, so that more blocks can be folded away with
TryToSimplifyUncondBranchFromEmptyBlock because there are less
conflicts in the phi node.
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2011-06-18 10:28:47 +00:00
Bill Wendling
6a648b8538
If the block that we're threading through is jumped to by an indirect branch,
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then we don't want to set the destination in the indirect branch to the
destination. This is because the indirect branch needs its destinations to have
had their block addresses taken. This isn't so of the new critical edge that's
split during this process. If it turns out that the destination block has only
one predecessor, and that being a BB with an indirect branch, then it won't be
marked as 'used' and may be removed.
PR10072
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2011-06-04 09:42:04 +00:00
Frits van Bommel
5649ba70fb
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.
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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.
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2011-05-22 16:24:18 +00:00
Devang Patel
d3a1788da1
Reapply r131605. This time with a fix, which is to use NoFolder.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131673 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-19 20:52:46 +00:00
Rafael Espindola
216dde91d1
revert 131605 to fix PR9946.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131620 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-19 02:26:30 +00:00
Devang Patel
1f5812bd99
Use IRBuilder.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131609 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-19 00:13:33 +00:00
Devang Patel
1aa89a2f91
Use IRBuilder while simplifying unreachable.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131607 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-19 00:09:21 +00:00
Devang Patel
0b4ccdc98c
Use IRBuilder while simplifying conditional branch.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131605 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 23:59:51 +00:00
Devang Patel
02dd5418d2
Use IRBuilder while simplifying branch.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131598 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 23:18:47 +00:00
Devang Patel
176ec40cb1
Use IRBuilder while simplifying return instruction.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131580 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 21:33:11 +00:00
Devang Patel
b55d924b1e
Spread use of IRBuilder even more.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131571 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 20:53:17 +00:00
Devang Patel
007349dafd
Use IRBuilder while simplifying switch instruction.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131566 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 20:35:38 +00:00
Devang Patel
d46ba26a6b
Use IRBuilder while simplifying unwind.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131561 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 20:01:18 +00:00
Devang Patel
d3372b85e6
Use IRBuilder while simplifying terminator.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131552 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 18:43:31 +00:00
Devang Patel
a23812cfbd
Use IRBuilder while simplifying unconditional branch.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131551 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 18:28:48 +00:00
Devang Patel
f60364de44
Use IRBuilder while folding two entry PHINode.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131548 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 18:16:44 +00:00
Devang Patel
3e410c6607
Set up IRBuilder for use during simplification.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131545 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18 18:01:27 +00:00
Devang Patel
d80e8ed2fa
Preseve line numbers while simplifying CFG.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131508 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-17 23:29:05 +00:00
Benjamin Kramer
10fcfb53fd
SimplifyCFG: Use ComputeMaskedBits to prune dead cases from switch instructions.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131345 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-14 15:57:25 +00:00
Peter Collingbourne
57808b3da0
SimplifyCFG: Expose phi node folding cost threshold as command line parameter
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130528 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-29 18:47:38 +00:00
Peter Collingbourne
f15907fead
SimplifyCFG: Add CostRemaining parameter to DominatesMergePoint
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130527 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-29 18:47:31 +00:00
Peter Collingbourne
8a70192b51
SimplifyCFG: Add Trunc, ZExt and SExt to the list of cheap instructions for phi node folding
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130526 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-29 18:47:25 +00:00
Chris Lattner
3c6e746b5f
rework FoldBranchToCommonDest to exit earlier when there is a bonus
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instruction around, reducing work.
Greatly simplify handling of debug instructions. There is no need to
build up a vector of them and then move them into the one predecessor
if we're processing a block. Instead just rescan the block and *copy*
them into the pred. If a block gets merged into multiple preds, this
will retain more debug info.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129502 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-14 02:44:53 +00:00
Chris Lattner
c8fbc34869
comment cleanup, use moveBefore instead of removeFromParent+insertBefore.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129319 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-11 23:24:57 +00:00
Devang Patel
60d490cdc7
Do not let debug info interfer with branch folding.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129114 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-07 23:11:25 +00:00
Devang Patel
949666ea16
While hoisting common code from if/else, hoist debug info intrinsics if they match.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129078 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-07 17:27:36 +00:00
Devang Patel
ae6c95b58e
Simplify. isIdenticalToWhenDefined() checks opcode.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129041 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-07 00:30:15 +00:00
Devang Patel
d418194036
While folding branch to a common destination into a predecessor, copy dbg values also.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129035 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-06 22:37:20 +00:00