Displaying 5 results from an estimated 5 matches for "vcmpe".
2019 Oct 01
5
PR43374 - when should comparing NaN values raise a floating point exception?
...K for <, <=, > and >= to raise an exception when argument values are NaNs. It is not OK for == an != to raise an exception when argument values are NaNs.
Therefore,
int bar(float x) {
return x!=x ? 0 : 1;
}
should not produce an exception when x is NaN, and hence a vcmp rather than vcmpe instruction should be produced when generating ARM code for this.
http://llvm.org/viewvc/llvm-project?rev=294945&view=rev introduced support for generating vcmp instead of vcmpe for equality comparisons. How come vcmpe is generated for (x!=x)?
The answer is that InstCombine transforms the equ...
2019 Oct 08
2
PR43374 - when should comparing NaN values raise a floating point exception?
...g
behaviour.
>
> Now, send the optimized IR to codegen:
> define i32 @is_nan(float %x) {
> %cmp = fcmp uno float %x, 0.000000e+00
> %r = zext i1 %cmp to i32
> ret i32 %r
> }
>
> $ llc -o - fpexception.ll -mtriple=armv7a
> vmov s0, r0
> mov r0, #0
> vcmpe.f32 s0, s0
> vmrs APSR_nzcv, fpscr
> movwvs r0, #1
> bx lr
>
> We produced "vcmpe" for code that should never cause an FP exception. ARM
> codegen bug?
sorry, the arm code gen is right here, the bug is in clang.
>
> On Tue, Oct 1, 2019 at 5:45 AM Kristof...
2019 Oct 01
2
PR43374 - when should comparing NaN values raise a floating point exception?
...raise an exception when argument values are NaNs. It is not OK for == an != to raise an exception when argument values are NaNs.
>
> Therefore,
>
> int bar(float x) {
> return x!=x ? 0 : 1;
> }
>
> should not produce an exception when x is NaN, and hence a vcmp rather than vcmpe instruction should be produced when generating ARM code for this.
>
> https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fllvm.org%2Fviewvc%2Fllvm-project%3Frev%3D294945%26view%3Drev&data=02%7C01%7CKevin.Neal%40sas.com%7C1c2441d90c5b4d3c4e6408d7467aa4cc%7Cb1c14d5c362545b3...
2011 May 26
2
[LLVMdev] LLVM CodeGen Engineer job opening with Apple's compiler team
Hi all,
LLVM CodeGen and Tools team at Apple is looking for exceptional compiler engineers. This is a great opportunity to work with many of the leaders in the LLVM community.
If you are interested in this position, please send your resume / CV and relevant information to evan.cheng at apple.com
Thanks,
Evan
Job description
The Apple compiler team is seeking an engineer who is strongly
2011 May 27
1
[LLVMdev] Question about ARM/vfp/NEON code generation
...#-4]
vmov s0, r0
str r1, [r7, #-8]
vmov s1, r1
str r2, [r7, #-12]
vmov s2, r2
vldr.32 s3, [r7, #-4]
vldr.32 s4, [r7, #-8]
vmul.f32 s3, s3, s4
vstr.32 s3, [r7, #-16]
vldr.32 s4, [r7, #-12]
vcmpe.f32 s3, s4
vmrs apsr_nzcv, fpscr
vstr.32 s0, [sp, #16]
vstr.32 s2, [sp, #12]
vstr.32 s1, [sp, #8]
ble LBB20_2
@ BB#1: @ %bb
vldr.32 s0, [r7, #-16]
ldr r0, LCPI20_0
LPC20_0:
add r0,...