getelementptr. Despite only doing so in the case where x is a known
array object and c can be converted to an index within range, this
could still be invalid if c is actually the address of an object
allocated outside of LLVM. Also, SCEVExpander, the original motivation
for this code, has since been improved to avoid inttoptr+ptroint in
more cases.
llvm-svn: 96950
operators.
The test difference is just due to the multiplication operands
being commuted (and thus requiring a more elaborate match). In
optimized code, that expression would be folded.
llvm-svn: 96816
cases, and implement target-independent folding rules for alignof and
offsetof. Also, reassociate reassociative operators when it leads to
more folding.
Generalize ScalarEvolution's isOffsetOf to recognize offsetof on
arrays. Rename getAllocSizeExpr to getSizeOfExpr, and getFieldOffsetExpr
to getOffsetOfExpr, for consistency with analagous ConstantExpr routines.
Make the target-dependent folder promote GEP array indices to
pointer-sized integers, to make implicit casting explicit and exposed
to subsequent folding.
And add a bunch of testcases for this new functionality, and a bunch
of related existing functionality.
llvm-svn: 94987
ConstantExpr, not just the top-level operator. This allows it to
fold many more constants.
Also, make GlobalOpt call ConstantFoldConstantExpression on
GlobalVariable initializers.
llvm-svn: 89659
non-type-safe constant initializers. This sort of thing happens
quite a bit for 4-byte loads out of string constants, unions,
bitfields, and an interesting endianness check from sqlite, which
is something like this:
const int sqlite3one = 1;
# define SQLITE_BIGENDIAN (*(char *)(&sqlite3one)==0)
# define SQLITE_LITTLEENDIAN (*(char *)(&sqlite3one)==1)
# define SQLITE_UTF16NATIVE (SQLITE_BIGENDIAN?SQLITE_UTF16BE:SQLITE_UTF16LE)
all of these macros now constant fold away.
This implements PR3152 and is based on a patch started by Eli, but heavily
modified and extended.
llvm-svn: 84936
Analysis/ConstantFolding.cpp. This doesn't change the behavior of
instcombine but makes other clients of ConstantFoldInstruction
able to handle loads. This was partially extracted from Eli's patch
in PR3152.
llvm-svn: 84836
how to fold notionally-out-of-bounds array getelementptr indices instead
of just doing these in lib/Analysis/ConstantFolding.cpp, because it can
be done in a fairly general way without TargetData, and because not all
constants are visited by lib/Analysis/ConstantFolding.cpp. This enables
more constant folding.
Also, set the "inbounds" flag when the getelementptr indices are
one-past-the-end.
llvm-svn: 81483
and exact flags. Because ConstantExprs are uniqued, creating an
expression with this flag causes all expressions with the same operands
to have the same flag, which may not be safe. Add, sub, mul, and sdiv
ConstantExprs are usually folded anyway, so the main interesting flag
here is inbounds, and the constant folder already knows how to set the
inbounds flag automatically in most cases, so there isn't an urgent need
for the API support.
This can be reconsidered in the future, but for now just removing these
API bits eliminates a source of potential trouble with little downside.
llvm-svn: 80959
array member of a struct, it's possible to land in an arbitrary position
inside that struct, such that attempting to find further getelementptr
indices will fail. In such cases, folding cannot be done.
llvm-svn: 79485
static extents of the static array type, it causes GlobalOpt and
other passes to be more conservative. This canonicalization also
allows the constant folder to add "inbounds" to GEPs.
llvm-svn: 79440
Duncan Sands