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20a35c3fa5
allows other simplifications. For example, this compiles:
int isnegative(unsigned int X) {
return !(X < 2147483648U);
}
Into this code:
x86:
movl 4(%esp), %eax
shrl $31, %eax
ret
arm:
mov r0, r0, lsr #31
bx lr
thumb:
lsr r0, r0, #31
bx lr
instead of:
x86:
cmpl $0, 4(%esp)
sets %al
movzbl %al, %eax
ret
arm:
mov r3, #0
cmp r0, #0
movlt r3, #1
mov r0, r3
bx lr
thumb:
mov r2, #1
mov r1, #0
cmp r0, #0
blt LBB1_2 @entry
LBB1_1: @entry
cpy r2, r1
LBB1_2: @entry
cpy r0, r2
bx lr
Testcase here: test/CodeGen/Generic/ispositive.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35883 91177308-0d34-0410-b5e6-96231b3b80d8
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for the Low Level Virtual Machine, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the HTML documentation provided in docs/index.html for further assistance with LLVM.