On 9/24/24 2:57 AM, Eikansh Gupta wrote:
This patch simplify `(trunc)copysign ((extend)x, CST)` to `copysign (x,
-1.0/1.0)`
depending on the sign of CST. Previously, it was simplified to `copysign (x,
CST)`.
It can be optimized as the sign of the CST matters, not the value.
The patch also simplify `(trunc)abs (extend x)` to `abs (x)`.
PR tree-optimization/112472
gcc/ChangeLog:
* match.pd ((trunc)copysign ((extend)x, -CST) --> copysign (x, -1.0)):
New pattern.
((trunc)abs (extend x) --> abs (x)): New pattern.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr112472.c: New test.
One might argue that -0.0/+0.0 are even better than -1.0/1.0 as the 0.0
variants are cheaper to construct.
You'd have to check that we honor signed zeros....
jeff
