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[PATCH] match.pd: Fold x/sqrt(x) to sqrt(x)

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This patch adds a pattern in match.pd folding x/sqrt(x) to sqrt(x) for -funsafe-math-optimizations. Test cases were added for double, float, and long double.

The patch was bootstrapped and regtested on aarch64-linux-gnu, no regression.
Ok for mainline?

Signed-off-by: Jennifer Schmitz <jschmitz@nvidia.com>

gcc/

	* match.pd: Fold x/sqrt(x) to sqrt(x).

gcc/testsuite/

	* gcc.dg/tree-ssa/sqrt_div.c: New test.
This commit is contained in:
Jennifer Schmitz 2024-07-03 14:40:42 +02:00 • committed by Kyrylo Tkachov
parent 640f0f3e2b
commit 8dc5ad3ce8
2 changed files with 27 additions and 0 deletions
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4
gcc/match.pd
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@ -7770,6 +7770,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
when the operand has that value.) */
(if (flag_unsafe_math_optimizations)
/* Simplify x / sqrt(x) -> sqrt(x). */
(simplify
(rdiv @0 (SQRT @0)) (SQRT @0))
/* Simplify sqrt(x) * sqrt(x) -> x. */
(simplify
(mult (SQRT_ALL@1 @0) @1)

23
gcc/testsuite/gcc.dg/tree-ssa/sqrt_div.c Normal file
View file

@ -0,0 +1,23 @@
/* { dg-do compile } */
/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
/* { dg-require-effective-target c99_runtime } */
#define T(n, type, fname) \
type f##n (type x) \
{ \
type t1 = __builtin_##fname (x); \
type t2 = x / t1; \
return t2; \
}
T(1, double, sqrt)
/* { dg-final { scan-tree-dump "gimple_simplified to t2_\[0-9\]+ = __builtin_sqrt .x_\[0-9\]*.D.." "forwprop1" } } */
T(2, float, sqrtf )
/* { dg-final { scan-tree-dump "gimple_simplified to t2_\[0-9\]+ = __builtin_sqrtf .x_\[0-9\]*.D.." "forwprop1" } } */
T(3, long double, sqrtl)
/* { dg-final { scan-tree-dump "gimple_simplified to t2_\[0-9\]+ = __builtin_sqrtl .x_\[0-9\]*.D.." "forwprop1" } } */