The included test case is derived from one of the GCC compatibility tests.
The problem arises after the selection DAG has been converted to type-legalized
form. The combiner first sees a 64-bit load that can be converted into a
pre-increment form. The original load feeds into a SRL that isolates the
upper 32 bits of the loaded doubleword. This looks like an opportunity for
DAGCombiner::ReduceLoadWidth() to replace the 64-bit load with a 32-bit load.
However, this transformation is not valid, as the replacement load is not
a pre-increment load. The pre-increment load produces an extra result,
which feeds a subsequent add instruction. The replacement load only has
one result value, and this value is propagated to all uses of the pre-
increment load, including the add. Because the add is looking for the
second result value as its operand, it ends up attempting to add a constant
to a token chain, resulting in a crash.
So the patch simply disables this transformation for any load with more than
two result values.
llvm-svn: 172480
Now that it behaves itself in terms of streamer independence (r172450), this
method can be moved to MCAsmParser to be available to all extensions,
overriding, etc.
-- -This line, and those below, will be ignored--
M lib/MC/MCParser/AsmParser.cpp
M include/llvm/MC/MCParser/MCAsmParser.h
llvm-svn: 172451
The aim of this patch is to fix the following piece of code in the
platform-independent AsmParser:
void AsmParser::CheckForValidSection() {
if (!ParsingInlineAsm && !getStreamer().getCurrentSection()) {
TokError("expected section directive before assembly directive");
Out.SwitchSection(Ctx.getMachOSection(
"__TEXT", "__text",
MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
0, SectionKind::getText()));
}
}
This was added for the "-n" option of llvm-mc.
The proposed fix adds another virtual method to MCStreamer, called
InitToTextSection. Conceptually, it's similar to the existing
InitSections which initializes all common sections and switches to
text. The new method is implemented by each platform streamer in a way
that it sees fit. So AsmParser can now do this:
void AsmParser::CheckForValidSection() {
if (!ParsingInlineAsm && !getStreamer().getCurrentSection()) {
TokError("expected section directive before assembly directive");
Out.InitToTextSection();
}
}
Which is much more reasonable.
llvm-svn: 172450
Since it's used by extensions. One further step to fully decoupling
GenericAsmParser from an intimate knowledge of the internals of AsmParser,
pointing it to the MCASmParser interface instead (like all other parser
extensions do).
Since this change moves the MacroArgument type to the interface header, it's
renamed to be a bit more descriptive in a general context.
llvm-svn: 172449
The methods are also exposed via the MCAsmParser interface, which allows more
than one client to control them. Previously, GenericAsmParser was playing with
a member var in AsmParser directly (by virtue of being its friend).
llvm-svn: 172440