EAX = ..., AX<imp-def>
...
= AX
This creates a double-def. Apparently this used to be necessary but is no longer needed.
Thanks to Anton for pointing this out. Anton, I cannot create a test case without your uncommitted ARM patches. Please check in a test case for me.
llvm-svn: 72755
one new .cpp file, in preparation for merging in the Direct Object Emission
changes we're working on. No functional changes.
Fixed coding style issues on the original patch. Patch by Aaron Gray
llvm-svn: 72754
ADDC/ADDE use MVT::i1 (later, whatever it gets legalized to)
instead of MVT::Flag. Remove CARRY_FALSE in favor of 0; adjust
all target-independent code to use this format.
Most targets will still produce a Flag-setting target-dependent
version when selection is done. X86 is converted to use i32
instead, which means TableGen needs to produce different code
in xxxGenDAGISel.inc. This keys off the new supportsHasI1 bit
in xxxInstrInfo, currently set only for X86; in principle this
is temporary and should go away when all other targets have
been converted. All relevant X86 instruction patterns are
modified to represent setting and using EFLAGS explicitly. The
same can be done on other targets.
The immediate behavior change is that an ADC/ADD pair are no
longer tightly coupled in the X86 scheduler; they can be
separated by instructions that don't clobber the flags (MOV).
I will soon add some peephole optimizations based on using
other instructions that set the flags to feed into ADC.
llvm-svn: 72707
failure during llvm-gcc bootstrap:
Assertion failed: (!Tmp2.getNode() && "Can't legalize BR_CC with legal condition!"), function ExpandNode, file /Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmCore.roots/llvmCore~obj/src/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp, line 2923.
/Volumes/Sandbox/Buildbot/llvm/full-llvm/build/llvmgcc42.roots/llvmgcc42~obj/src/gcc/libgcc2.c:1727: internal compiler error: Abort trap
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://developer.apple.com/bugreporter> for instructions.
llvm-svn: 72530
This is basically the end of this series of patches for LegalizeDAG; the
remaining special cases can't be removed without more infrastructure
work. There's a FIXME for each relevant opcode near the beginning of
SelectionDAGLegalize::LegalizeOp.
llvm-svn: 72514
e.g.
orl $65536, 8(%rax)
=>
orb $1, 10(%rax)
Since narrowing is not always a win, e.g. i32 -> i16 is a loss on x86, dag combiner consults with the target before performing the optimization.
llvm-svn: 72507
entries as there are basic blocks in the function. LiveVariables::getVarInfo
creates a VarInfo struct for every register in the function, leading to
quadratic space use. This patch changes the BitVector to a SparseBitVector,
which doesn't help the worst-case memory use but does reduce the actual use in
very long functions with short-lived variables.
llvm-svn: 72426
doesn't split legal vector operands. This is necessary because the
type legalization (and therefore, vector splitting) code will be going
away soon.
llvm-svn: 72349
The DAGCombiner created a negative shiftamount, stored in an
unsigned variable. Later the optimizer eliminated the shift entirely as being
undefined.
Example: (srl (shl X, 56) 48). ShiftAmt is 4294967288.
Fix it by checking that the shiftamount is positive, and storing in a signed
variable.
llvm-svn: 72331
will allow simplifying LegalizeDAG to eliminate type legalization. (I
have a patch to do that, but it's not quite finished; I'll commit it
once it's finished and I've fixed any review comments for this patch.)
See the comment at the beginning of
lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp for more details on the
motivation for this patch.
llvm-svn: 72325
code in preparation for code generation. The main thing it does
is handle the case when eh.exception calls (and, in a future
patch, eh.selector calls) are far away from landing pads. Right
now in practice you only find eh.exception calls close to landing
pads: either in a landing pad (the common case) or in a landing
pad successor, due to loop passes shifting them about. However
future exception handling improvements will result in calls far
from landing pads:
(1) Inlining of rewinds. Consider the following case:
In function @f:
...
invoke @g to label %normal unwind label %unwinds
...
unwinds:
%ex = call i8* @llvm.eh.exception()
...
In function @g:
...
invoke @something to label %continue unwind label %handler
...
handler:
%ex = call i8* @llvm.eh.exception()
... perform cleanups ...
"rethrow exception"
Now inline @g into @f. Currently this is turned into:
In function @f:
...
invoke @something to label %continue unwind label %handler
...
handler:
%ex = call i8* @llvm.eh.exception()
... perform cleanups ...
invoke "rethrow exception" to label %normal unwind label %unwinds
unwinds:
%ex = call i8* @llvm.eh.exception()
...
However we would like to simplify invoke of "rethrow exception" into
a branch to the %unwinds label. Then %unwinds is no longer a landing
pad, and the eh.exception call there is then far away from any landing
pads.
(2) Using the unwind instruction for cleanups.
It would be nice to have codegen handle the following case:
invoke @something to label %continue unwind label %run_cleanups
...
handler:
... perform cleanups ...
unwind
This requires turning "unwind" into a library call, which
necessarily takes a pointer to the exception as an argument
(this patch also does this unwind lowering). But that means
you are using eh.exception again far from a landing pad.
(3) Bugpoint simplifications. When bugpoint is simplifying
exception handling code it often generates eh.exception calls
far from a landing pad, which then causes codegen to assert.
Bugpoint then latches on to this assertion and loses sight
of the original problem.
Note that it is currently rare for this pass to actually do
anything. And in fact it normally shouldn't do anything at
all given the code coming out of llvm-gcc! But it does fire
a few times in the testsuite. As far as I can see this is
almost always due to the LoopStrengthReduce codegen pass
introducing pointless loop preheader blocks which are landing
pads and only contain a branch to another block. This other
block contains an eh.exception call. So probably by tweaking
LoopStrengthReduce a bit this can be avoided.
llvm-svn: 72276
