maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
50,710 Commits 23 Branches 0 Tags 2.2 GiB
Commit Graph

22 Commits

Author SHA1 Message Date
Chris Lattner 98d89d1b1b Make jump threading substantially more powerful, in the following ways: 
1. Make it fold blocks separated by an unconditional branch.  This enables
   jump threading to see a broader scope.
2. Make jump threading able to eliminate locally redundant loads when they
   feed the branch condition of a block.  This frequently occurs due to
   reg2mem running.
3. Make jump threading able to eliminate *partially redundant* loads when
   they feed the branch condition of a block.  This is common in code with
   lots of loads and stores like C++ code and 255.vortex.

This implements thread-loads.ll and rdar://6402033.

Per the fixme's, several pieces of this should be moved into Transforms/Utils.

llvm-svn: 60148
 2008-11-27 05:07:53 +00:00
Dan Gohman a79db30d28 Tidy up several unbeseeming casts from pointer to intptr_t. 
llvm-svn: 55779
 2008-09-04 17:05:41 +00:00
Dan Gohman fa1211f69b Enable first-class aggregates support. 
Remove the GetResultInst instruction. It is still accepted in LLVM assembly
and bitcode, where it is now auto-upgraded to ExtractValueInst. Also, remove
support for return instructions with multiple values. These are auto-upgraded
to use InsertValueInst instructions.

The IRBuilder still accepts multiple-value returns, and auto-upgrades them
to InsertValueInst instructions.

llvm-svn: 53941
 2008-07-23 00:34:11 +00:00
Duncan Sands 698348dfac Fix some constructs that gcc-4.4 warns about. 
llvm-svn: 51591
 2008-05-27 11:50:51 +00:00
Dan Gohman f96e1371e8 Tidy up BasicBlock::getFirstNonPHI, and change a bunch of places to 
use it instead of duplicating its functionality.

llvm-svn: 51499
 2008-05-23 21:05:58 +00:00
Matthijs Kooijman 5148a4ba66 Fix typo. 
llvm-svn: 51303
 2008-05-20 07:26:45 +00:00
Dan Gohman d78c400b5b Clean up the use of static and anonymous namespaces. This turned up 
several things that were neither in an anonymous namespace nor static
but not intended to be global.

llvm-svn: 51017
 2008-05-13 00:00:25 +00:00
Chris Lattner e7f0afe168 restore doxygen comment. 
llvm-svn: 50881
 2008-05-09 04:43:13 +00:00
Gordon Henriksen 829046b0b4 Improve pass documentation and comments. 
Patch by Matthijs Kooijman!

llvm-svn: 50861
 2008-05-08 17:46:35 +00:00
Chris Lattner de68fabb35 fix typo Duncan noticed 
llvm-svn: 50699
 2008-05-06 02:31:18 +00:00
Chris Lattner 8ed8e3d0e6 Fix a crash when threading a block that includes a MRV call result. 
DemoteRegToStack doesn't work with MRVs yet, because it relies on the
ability to load/store things.

This fixes PR2285.

llvm-svn: 50667
 2008-05-05 20:21:22 +00:00
Chris Lattner f7de528463 Don't infininitely thread branches when a threaded edge 
goes back to the block, e.g.:

  Threading edge through bool from 'bb37.us.thread3829' to 'bb37.us' with cost: 1, across block:

bb37.us:		; preds = %bb37.us.thread3829, %bb37.us, %bb33
	%D1361.1.us = phi i32 [ %tmp36, %bb33 ], [ %D1361.1.us, %bb37.us ], [ 0, %bb37.us.thread3829 ]		; <i32> [#uses=2]
	%tmp39.us = icmp eq i32 %D1361.1.us, 0		; <i1> [#uses=1]
	br i1 %tmp39.us, label %bb37.us, label %bb42.us

llvm-svn: 50251
 2008-04-25 04:12:29 +00:00
Chris Lattner 37e9c187b0 Start doing the significantly useful part of jump threading: handle cases 
where a comparison has a phi input and that phi is a constant.  For example,
stuff like:

  Threading edge through bool from 'bb2149' to 'bb2231' with cost: 1, across block:
bb2237:		; preds = %bb2231, %bb2149
	%tmp2328.rle = phi i32 [ %tmp2232, %bb2231 ], [ %tmp2232439, %bb2149 ]		; <i32> [#uses=2]
	%done.0 = phi i32 [ %done.2, %bb2231 ], [ 0, %bb2149 ]		; <i32> [#uses=1]
	%tmp2239 = icmp eq i32 %done.0, 0		; <i1> [#uses=1]
	br i1 %tmp2239, label %bb2231, label %bb2327

or

bb38.i298:		; preds = %bb33.i295, %bb1693
	%tmp39.i296.rle = phi %struct.ibox* [ null, %bb1693 ], [ %tmp39.i296.rle1109, %bb33.i295 ]		; <%struct.ibox*> [#uses=2]
	%minspan.1.i291.reg2mem.1 = phi i32 [ 32000, %bb1693 ], [ %minspan.0.i288, %bb33.i295 ]		; <i32> [#uses=1]
	%tmp40.i297 = icmp eq %struct.ibox* %tmp39.i296.rle, null		; <i1> [#uses=1]
	br i1 %tmp40.i297, label %implfeeds.exit311, label %bb43.i301

This triggers thousands of times in spec.

llvm-svn: 50110
 2008-04-22 21:40:39 +00:00
Chris Lattner d5425e8f8d Dig through multiple levels of AND to thread jumps if needed. 
llvm-svn: 50106
 2008-04-22 20:46:09 +00:00
Chris Lattner 3df4c15dc7 Teach jump threading to thread through blocks like: 
br (and X, phi(Y, Z, false)), label L1, label L2

This triggers once on 252.eon and 6 times on 176.gcc.  Blocks 
in question often look like this:

bb262:		; preds = %bb261, %bb248
	%iftmp.251.0 = phi i1 [ true, %bb261 ], [ false, %bb248 ]		; <i1> [#uses=4]
	%tmp270 = icmp eq %struct.rtx_def* %tmp.0.i, null		; <i1> [#uses=1]
	%bothcond = or i1 %iftmp.251.0, %tmp270		; <i1> [#uses=1]
	br i1 %bothcond, label %bb288, label %bb273

In this case, it is clear that it doesn't matter if tmp.0.i is null when coming from bb261.  When coming from bb248, it is all that matters.


Another random example:

check_asm_operands.exit:		; preds = %check_asm_operands.exit.thr_comm, %bb30.i, %bb12.i, %bb6.i413
	%tmp.0.i420 = phi i1 [ true, %bb6.i413 ], [ true, %bb12.i ], [ true, %bb30.i ], [ false, %check_asm_operands.exit.thr_comm ; <i1> [#uses=1]
	call void @llvm.stackrestore( i8* %savedstack ) nounwind 
	%tmp4389 = icmp eq i32 %added_sets_1.0, 0		; <i1> [#uses=1]
	%tmp4394 = icmp eq i32 %added_sets_2.0, 0		; <i1> [#uses=1]
	%bothcond80 = and i1 %tmp4389, %tmp4394		; <i1> [#uses=1]
	%bothcond81 = and i1 %bothcond80, %tmp.0.i420		; <i1> [#uses=1]
	br i1 %bothcond81, label %bb4398, label %bb4397

Here is the case from 252.eon:

bb290.i.i:		; preds = %bb23.i57.i.i, %bb8.i39.i.i, %bb100.i.i, %bb100.i.i, %bb85.i.i110
	%myEOF.1.i.i = phi i1 [ true, %bb100.i.i ], [ true, %bb100.i.i ], [ true, %bb85.i.i110 ], [ true, %bb8.i39.i.i ], [ false, %bb23.i57.i.i ]		; <i1> [#uses=2]
	%i.4.i.i = phi i32 [ %i.1.i.i, %bb85.i.i110 ], [ %i.0.i.i, %bb100.i.i ], [ %i.0.i.i, %bb100.i.i ], [ %i.3.i.i, %bb8.i39.i.i ], [ %i.3.i.i, %bb23.i57.i.i ]		; <i32> [#uses=3]
	%tmp292.i.i = load i8* %tmp16.i.i100, align 1		; <i8> [#uses=1]
	%tmp293.not.i.i = icmp ne i8 %tmp292.i.i, 0		; <i1> [#uses=1]
	%bothcond.i.i = and i1 %tmp293.not.i.i, %myEOF.1.i.i		; <i1> [#uses=1]
	br i1 %bothcond.i.i, label %bb202.i.i, label %bb301.i.i
  Factoring out 3 common predecessors.

On the path from any blocks other than bb23.i57.i.i, the load and compare 
are dead.

llvm-svn: 50096
 2008-04-22 07:05:46 +00:00
Chris Lattner e369c35a84 refactor some code, no functionality change. 
llvm-svn: 50094
 2008-04-22 06:36:15 +00:00
Chris Lattner bab7bec9c8 fix grammar-o, thanks to Duncan for noticing. 
llvm-svn: 50047
 2008-04-21 18:25:01 +00:00
Chris Lattner f6236cc2e9 Use the new SplitBlockPredecessors to implement a todo. 
llvm-svn: 50022
 2008-04-21 02:57:57 +00:00
Chris Lattner ff1c6e388c finish the first cut of a jump threading pass implementation. 
llvm-svn: 50006
 2008-04-20 22:39:42 +00:00
Chris Lattner 9c1f1a82bf we can only thread blocks when there is a pred we can determine the succ of. 
llvm-svn: 50003
 2008-04-20 21:18:09 +00:00
Chris Lattner 2115722ffa improve comments, infrastructure, and add some validity checks for threading. 
Add a cost function.

llvm-svn: 50002
 2008-04-20 21:13:06 +00:00
Chris Lattner b3b6007c8b Add a new Jump Threading pass, which will handle cases 
such as those in PR2235.  Right now the pass is not very
effective. :)

llvm-svn: 50000
 2008-04-20 20:35:01 +00:00