llvm-project/llvm/test/CodeGen/X86/sub.ll

; RUN: llc -mtriple=i686-- < %s | FileCheck %s

define i32 @test1(i32 %x) {
  %xor = xor i32 %x, 31
  %sub = sub i32 32, %xor
  ret i32 %sub
; CHECK-LABEL: test1:
; CHECK:      xorl $-32
; CHECK-NEXT: addl $33
; CHECK-NEXT: ret
}
X86: Do not use llc -march in tests. `llc -march` is problematic because it only switches the target architecture, but leaves the operating system unchanged. This occasionally leads to indeterministic tests because the OS from LLVM_DEFAULT_TARGET_TRIPLE is used. However we can simply always use `llc -mtriple` instead. This changes all the tests to do this to avoid people using -march when they copy and paste parts of tests. See also the discussion in https://reviews.llvm.org/D35287 llvm-svn: 309774 2017-08-02 08:28:10 +08:00			`; RUN: llc -mtriple=i686-- < %s \| FileCheck %s`
Add a neat little two's complement hack for x86. On x86 we can't encode an immediate LHS of a sub directly. If the RHS comes from a XOR with a constant we can fold the negation into the xor and add one to the immediate of the sub. Then we can turn the sub into an add, which can be commuted and encoded efficiently. This code is generated for __builtin_clz and friends. llvm-svn: 136167 2011-07-27 06:42:13 +08:00
			`define i32 @test1(i32 %x) {`
			`%xor = xor i32 %x, 31`
			`%sub = sub i32 32, %xor`
			`ret i32 %sub`
Convert CodeGen//.ll tests to use the new CHECK-LABEL for easier debugging. No functionality change and all tests pass after conversion. This was done with the following sed invocation to catch label lines demarking function boundaries: sed -i '' "s/^;\( \)\([A-Z0-9_]\):\( \)test\([A-Za-z0-9_-]\):\( \)$/;\1\2-LABEL:\3test\4:\5/g" test/CodeGen//*.ll which was written conservatively to avoid false positives rather than false negatives. I scanned through all the changes and everything looks correct. llvm-svn: 186258 2013-07-14 04:38:47 +08:00			`; CHECK-LABEL: test1:`
Add a neat little two's complement hack for x86. On x86 we can't encode an immediate LHS of a sub directly. If the RHS comes from a XOR with a constant we can fold the negation into the xor and add one to the immediate of the sub. Then we can turn the sub into an add, which can be commuted and encoded efficiently. This code is generated for __builtin_clz and friends. llvm-svn: 136167 2011-07-27 06:42:13 +08:00			`; CHECK: xorl $-32`
			`; CHECK-NEXT: addl $33`
			`; CHECK-NEXT: ret`
			`}`