This obviously helps a lot if the division would be turned into a libcall
(think i64 udiv on i386), but div is also one of the few remaining instructions
on modern CPUs that become more expensive when the bitwidth gets bigger.

This also helps register pressure on i386 when dividing chars, divb needs
two 8-bit parts of a 16 bit register as input where divl uses two registers.

int foo(unsigned char a) { return a/10; }
int bar(unsigned char a, unsigned char b) { return a/b; }

compiles into (x86_64)
_foo:
  imull $205, %edi, %eax
  shrl  $11, %eax
  ret
_bar:
  movzbl        %dil, %eax
  divb  %sil, %al
  movzbl        %al, %eax
  ret

llvm-svn: 130615

This folds away silly stuff like (a&255)/1000 -> 0.

llvm-svn: 130614

llvm-svn: 130613

is a bit ugly, but doing it on the base MCStreamer would be redundant
with the object streamer which does it using SD.

llvm-svn: 130611

llvm-svn: 130609

llvm-svn: 130599

This could happen when trying to use a value that had been eliminated after dead
code elimination and folding loads.

llvm-svn: 130597

llvm-svn: 130596

llvm-svn: 130589

the final assembly. It is the same technique used when targeting
assemblers that don't support .loc.

llvm-svn: 130587

llvm-svn: 130585

llvm-svn: 130582

llvm-svn: 130568

llvm-svn: 130567

llvm-svn: 130562

Make FastEmit_ri_ try a bit harder to succeed for supported operations; FastEmit_i can fail for non-Thumb2 ARM.  Makes ARMSimplifyAddress work correctly, and reduces the number of fast-isel bailouts on non-Thumb ARM.

llvm-svn: 130560

llvm-svn: 130558

llvm-svn: 130557

llvm-svn: 130552

llvm-svn: 130551

if it ever did it needs the def machinery.

llvm-svn: 130549

Filter out pattterns from the FastISel emitter which it doesn't actually know how to handle.  No significant functionality change at the moment, but it's necessary for some changes I'm planning.

llvm-svn: 130547

llvm-svn: 130546

lets this code be used when producing assembly code for old assemblers without
uleb support.

llvm-svn: 130544

llvm-svn: 130543

llvm-svn: 130542

llvm-svn: 130540

Fix a rather obscure crash caused by ARM fast-isel generating code which redefines a register.
rdar://problem/9338332 .

llvm-svn: 130539

llvm-svn: 130536

for bools, but is a start.

llvm-svn: 130534

issue.

llvm-svn: 130530

llvm-svn: 130529

llvm-svn: 130528

llvm-svn: 130527

llvm-svn: 130526

currently used, because variables don't get reported as being "defined".

llvm-svn: 130524

MC: Change variable symbols to be recognized as defined, by assigning their sections based on FindAssociatedSection().

llvm-svn: 130523

llvm-svn: 130522

llvm-svn: 130520

MC/Mach-O: Find section ordinal's by looking at the symbol, instead of assuming they are present in a fragment.

llvm-svn: 130519