llvm-6502

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History

Evan Cheng 70e10d3fe4 This is another case where instcombine demanded bits optimization created

large immediates. Add dag combine logic to recover in case the large
immediates doesn't fit in cmp immediate operand field.

int foo(unsigned long l) {
  return (l>> 47) == 1;
}

we produce

  %shr.mask = and i64 %l, -140737488355328
  %cmp = icmp eq i64 %shr.mask, 140737488355328
  %conv = zext i1 %cmp to i32
  ret i32 %conv

which codegens to

movq    $0xffff800000000000,%rax
andq    %rdi,%rax
movq    $0x0000800000000000,%rcx
cmpq    %rcx,%rax
sete    %al
movzbl    %al,%eax
ret

TargetLowering::SimplifySetCC would transform
(X & -256) == 256 -> (X >> 8) == 1
if the immediate fails the isLegalICmpImmediate() test. For x86,
that's immediates which are not a signed 32-bit immediate.

Based on a patch by Eli Friedman.

PR10328
rdar://9758774


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160346 91177308-0d34-0410-b5e6-96231b3b80d8

2012-07-17 06:53:39 +00:00

Analysis

Move llvm/Support/TypeBuilder.h -> llvm/TypeBuilder.h. This completes

2012-07-15 23:45:24 +00:00

Archive

Include cstdio in a few place that depended on getting it transitively through StringExtras.h

2012-03-23 11:35:30 +00:00

AsmParser

Extend the IL for selecting TLS models (PR9788)

2012-06-23 11:37:03 +00:00

Bitcode

llvm/lib: [CMake] Add explicit dependency to intrinsics_gen.