Commit Graph

8 Commits

Author SHA1 Message Date
Evan Cheng
2c755ba12a Re-apply 97040 with fix. This survives a ppc self-host llvm-gcc bootstrap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97310 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-27 07:36:59 +00:00
Daniel Dunbar
cfe30effbb Speculatively revert r97011, "Re-apply 96540 and 96556 with fixes.", again in
the hopes of fixing PPC bootstrap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97040 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-24 17:05:47 +00:00
Evan Cheng
97e6b8390b Re-apply 96540 and 96556 with fixes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97011 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-24 01:42:31 +00:00
Evan Cheng
c6feeb7fa9 These should not have been committed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96827 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-22 23:37:48 +00:00
Evan Cheng
6e5dfd4bf5 Instcombine constant folding can normalize gep with negative index to index with large offset. When instcombine objsize checking transformation sees these geps where the offset seemingly point out of bound, it should just return "i don't know" rather than asserting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96825 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-22 23:34:00 +00:00
Duncan Sands
3eba667081 Revert commits 96556 and 96640, because commit 96556 breaks the
dragonegg self-host build.  I reverted 96640 in order to revert
96556 (96640 goes on top of 96556), but it also looks like with
both of them applied the breakage happens even earlier.  The
symptom of the 96556 miscompile is the following crash:

  llvm[3]: Compiling AlphaISelLowering.cpp for Release build
  cc1plus: /home/duncan/tmp/tmp/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:4982: void llvm::SelectionDAG::ReplaceAllUsesWith(llvm::SDNode*, llvm::SDNode*, llvm::SelectionDAG::DAGUpdateListener*): Assertion `(!From->hasAnyUseOfValue(i) || From->getValueType(i) == To->getValueType(i)) && "Cannot use this version of ReplaceAllUsesWith!"' failed.
  Stack dump:
  0.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@_ZN4llvm19AlphaTargetLowering14LowerOperationENS_7SDValueERNS_12SelectionDAGE'
  g++: Internal error: Aborted (program cc1plus)

This occurs when building LLVM using LLVM built by LLVM (via
dragonegg).  Probably LLVM has miscompiled itself, though it
may have miscompiled GCC and/or dragonegg itself: at this point
of the self-host build, all of GCC, LLVM and dragonegg were built
using LLVM.  Unfortunately this kind of thing is extremely hard
to debug, and while I did rummage around a bit I didn't find any
smoking guns, aka obviously miscompiled code.

Found by bisection.

r96556 | evancheng | 2010-02-18 03:13:50 +0100 (Thu, 18 Feb 2010) | 5 lines

Some dag combiner goodness:
Transform br (xor (x, y)) -> br (x != y)
Transform br (xor (xor (x,y), 1)) -> br (x == y)
Also normalize (and (X, 1) == / != 1 -> (and (X, 1)) != / == 0 to match to "test on x86" and "tst on arm"

r96640 | evancheng | 2010-02-19 01:34:39 +0100 (Fri, 19 Feb 2010) | 16 lines

Transform (xor (setcc), (setcc)) == / != 1 to
(xor (setcc), (setcc)) != / == 1.

e.g. On x86_64
  %0 = icmp eq i32 %x, 0
  %1 = icmp eq i32 %y, 0
  %2 = xor i1 %1, %0
  br i1 %2, label %bb, label %return
=>
	testl   %edi, %edi
	sete    %al
	testl   %esi, %esi
	sete    %cl
	cmpb    %al, %cl
	je      LBB1_2



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96672 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-19 11:30:41 +00:00
Evan Cheng
97a35fc3a7 Transform (xor (setcc), (setcc)) == / != 1 to
(xor (setcc), (setcc)) != / == 1.

e.g. On x86_64
  %0 = icmp eq i32 %x, 0
  %1 = icmp eq i32 %y, 0
  %2 = xor i1 %1, %0
  br i1 %2, label %bb, label %return
=>
	testl   %edi, %edi
	sete    %al
	testl   %esi, %esi
	sete    %cl
	cmpb    %al, %cl
	je      LBB1_2


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96640 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-19 00:34:39 +00:00
Evan Cheng
d40d03e1bd Teach dag combine to fold the following transformation more aggressively:
(OP (trunc x), (trunc y)) -> (trunc (OP x, y))

Unfortunately this simple change causes dag combine to infinite looping. The problem is the shrink demanded ops optimization tend to canonicalize expressions in the opposite manner. That is badness. This patch disable those optimizations in dag combine but instead it is done as a late pass in sdisel.

This also exposes some deficiencies in dag combine and x86 setcc / brcond lowering. Teach them to look pass ISD::TRUNCATE in various places.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92849 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-06 19:38:29 +00:00