Fold c2 in (x << c1) | c2 where (c2 < c1)
e.g.
int test(int x) {
return (x << 3) + 7;
}
This can be codegen'd as:
leal 7(,%eax,8), %eax
llvm-svn: 28550
movw. That is we promote the destination operand to r16. So
%CH = TRUNC_R16_R8 %BP
is emitted as
movw %bp, %cx.
This is incorrect. If %cl is live, it would be clobbered.
Ideally we want to do the opposite, that is emitted it as
movb ??, %ch
But this is not possible since %bp does not have a r8 sub-register.
We are now defining a new register class R16_ which is a subclass of R16
containing only those 16-bit registers that have r8 sub-registers (i.e.
AX - DX). We isel the truncate to two instructions, a MOV16to16_ to copy the
value to the R16_ class, followed by a TRUNC_R16_R8.
Due to bug 770, the register colaescer is not going to coalesce between R16 and
R16_. That will be fixed later so we can eliminate the MOV16to16_. Right now, it
can only be eliminated if we are lucky that source and destination registers are
the same.
llvm-svn: 28164
that gets emitted as movl (for r32 to i16, i8) or a movw (for r16 to i8). And
if the destination gets allocated a subregister of the source operand, then
the instruction will not be emitted at all.
llvm-svn: 28119
x86 and ppc for 100% dense switch statements when relocations are non-PIC.
This support will be extended and enhanced in the coming days to support
PIC, and less dense forms of jump tables.
llvm-svn: 27947
* Add patterns to handle GlobalAddress, ConstantPool, etc.
MOV32ri to materialize these nodes in registers.
ADD32ri to handle %reg + GA, etc.
MOV32mi to handle store GA, etc. to memory.
llvm-svn: 26374
and ExternalSymbol.
- Use C++ code (rather than tblgen'd selection code) to match the above
mentioned leaf nodes. Do not mutate and nodes and do not record the
selection in CodeGenMap. These nodes should be safe to duplicate. This is
a performance win.
llvm-svn: 26335
proves to be worth 20% on Ptrdist/ks. Might be related to dependency
breaking support.
2. Added FsMOVAPSrr and FsMOVAPDrr as aliases to MOVAPSrr and MOVAPDrr. These
are used for FR32 / FR64 reg-to-reg copies.
3. Tell reg-allocator to generate MOVSSrm / MOVSDrm and MOVSSmr / MOVSDmr to
spill / restore FsMOVAPSrr and FsMOVAPDrr.
llvm-svn: 26241
- Added a new format for instructions where the source register is implied
and it is same as the destination register. Used for pseudo instructions
that clear the destination register.
llvm-svn: 25872
