information is not separated into a "base" and "sub" type. Eventually the
value-tracking logic will know about LValues and RValues, but not about
specialized LValues and RValues; separating the "kind" information into bits
indicating whether an ExprValue is an LValue or an RValue from the bits that
specify the actual value type makes this separation easier.
llvm-svn: 46329
APInt.
While some operators were already specifically overloaded for APSInt, others
resulted in using the overloaded operator methods in APInt, which would result
in the signedness bit being lost.
Modified the APSInt(APInt&) constructor to be "explicit" and to take an
extra (optional) flag to indicate the signedness. Making the ctor explicit
will catch any implicit conversations between APSInt -> APInt -> APSInt that
results in the signedness flag being lost.
llvm-svn: 46316
Added some workarounds for loss of signess information on some APSInt
operations. Considering the best route to integrate these into APSInt directly.
(FIXME's in GRConstants.cpp).
llvm-svn: 46310
This case returns the value in ST(0) and then has to convert it to an SSE
register. This causes significant codegen ugliness in some cases. For
example in the trivial fp-stack-direct-ret.ll testcase we used to generate:
_bar:
subl $28, %esp
call L_foo$stub
fstpl 16(%esp)
movsd 16(%esp), %xmm0
movsd %xmm0, 8(%esp)
fldl 8(%esp)
addl $28, %esp
ret
because we move the result of foo() into an XMM register, then have to
move it back for the return of bar.
Instead of hacking ever-more special cases into the call result lowering code
we take a much simpler approach: on x86-32, fp return is modeled as always
returning into an f80 register which is then truncated to f32 or f64 as needed.
Similarly for a result, we model it as an extension to f80 + return.
This exposes the truncate and extensions to the dag combiner, allowing target
independent code to hack on them, eliminating them in this case. This gives
us this code for the example above:
_bar:
subl $12, %esp
call L_foo$stub
addl $12, %esp
ret
The nasty aspect of this is that these conversions are not legal, but we want
the second pass of dag combiner (post-legalize) to be able to hack on them.
To handle this, we lie to legalize and say they are legal, then custom expand
them on entry to the isel pass (PreprocessForFPConvert). This is gross, but
less gross than the code it is replacing :)
This also allows us to generate better code in several other cases. For
example on fp-stack-ret-conv.ll, we now generate:
_test:
subl $12, %esp
call L_foo$stub
fstps 8(%esp)
movl 16(%esp), %eax
cvtss2sd 8(%esp), %xmm0
movsd %xmm0, (%eax)
addl $12, %esp
ret
where before we produced (incidentally, the old bad code is identical to what
gcc produces):
_test:
subl $12, %esp
call L_foo$stub
fstpl (%esp)
cvtsd2ss (%esp), %xmm0
cvtss2sd %xmm0, %xmm0
movl 16(%esp), %eax
movsd %xmm0, (%eax)
addl $12, %esp
ret
Note that we generate slightly worse code on pr1505b.ll due to a scheduling
deficiency that is unrelated to this patch.
llvm-svn: 46307
1. we already know the value is dead, so don't bother replacing
it with undef.
2. The very case the comment describes actually makes the load
live which asserts in deletenode. If we do the replacement
and the node becomes live, just treat it as new. This fixes
a failure on X86/2008-01-16-InvalidDAGCombineXform.ll with
some local changes in my tree.
llvm-svn: 46306
dead stuff around. This gets fed into the isel pass and causes certain foldings from
happening because nodes have extraneous uses floating around. For example, if we turned
foo(bar(x)) -> baz(x), we sometimes left bar(x) around.
llvm-svn: 46305
getNodeLabel(); these sequences allow the user to specify the characters '{',
'}', and '|' in the label, which facilitate breaking the label into multiple
record segments.
llvm-svn: 46283
precision integers. This won't actually work
(and most of the code is dead) unless the new
legalization machinery is turned on. While
there, I rationalized the handling of i1, and
removed some bogus (and unused) sextload patterns.
For i1, this could result in microscopically
better code for some architectures (not X86).
It might also result in worse code if annotating
with AssertZExt nodes turns out to be more harmful
than helpful.
llvm-svn: 46280
diagnose, and took even longer to fix. It has to do with rewriting of a message
receiver which is an 'ivar' reference. Fix, however, is to remove a code which
was not doing the right thing and no longer needed.
llvm-svn: 46279
abstract "L-values" and "R-values" when doing value tracking, and expanding
constant tracking to encompass tracking disjunctive sets of possible constants.
Further, the tree-walking is more efficient, as we don't blindly recurse the
tree if we won't generate new states.
llvm-svn: 46278
Chris Lattner