| Issue |
61617
|
| Summary |
handling trigonometric function under "-ffast-math"
|
| Labels |
|
| Assignees |
|
| Reporter |
k-arrows
|
Consider the following code under "-ffast-math".
```c
#include <math.h>
float f1(float x)
{
return tanf(x) * cosf(x);
}
float f2(float x)
{
return sinf(x) / tanf(x);
}
```
gcc
```asm
f1:
b sinf
f2:
b cosf
```
clang
```asm
f1: // @f1
stp d9, d8, [sp, #-32]! // 16-byte Folded Spill
stp x29, x30, [sp, #16] // 16-byte Folded Spill
add x29, sp, #16
fmov s8, s0
bl tanf
fmov s9, s0
fmov s0, s8
bl cosf
fmul s0, s9, s0
ldp x29, x30, [sp, #16] // 16-byte Folded Reload
ldp d9, d8, [sp], #32 // 16-byte Folded Reload
ret
f2: // @f2
stp d9, d8, [sp, #-32]! // 16-byte Folded Spill
stp x29, x30, [sp, #16] // 16-byte Folded Spill
add x29, sp, #16
fmov s8, s0
bl sinf
fmov s9, s0
fmov s0, s8
bl tanf
fdiv s0, s9, s0
ldp x29, x30, [sp, #16] // 16-byte Folded Reload
ldp d9, d8, [sp], #32 // 16-byte Folded Reload
ret
```
https://godbolt.org/z/Kf9r1aPj7
This difference is not specific to aarch64.
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