Chris Lattner 6bf77500c6 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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50096 91177308-0d34-0410-b5e6-96231b3b80d8		2008-04-22 07:05:46 +00:00
..
Hello	Remove attribution from file headers, per discussion on llvmdev.	2007-12-29 20:36:04 +00:00
Instrumentation	Use Intrinsic::getDeclaration in more places.	2008-04-07 13:45:04 +00:00
IPO	don't assume that the argument passed to fprintf("%s" is a string. This	2008-04-21 03:18:33 +00:00
Scalar	Teach jump threading to thread through blocks like:	2008-04-22 07:05:46 +00:00
Utils	Move SplitBlockPredecessors out of loopsimplify into BasicBlockUtils.h	2008-04-21 01:28:02 +00:00
Makefile	remove attribution from lib Makefiles.	2007-12-29 20:09:26 +00:00