Hi all,
This is a simple patch to enable two simplifications for UNSIGNED_FLOAT
expression.
For the following rtx patterns, they can be simplified when the integer
x can be
represented in float mode without precision loss:
float_truncate (float x) --> float x
float_extend (float x) --> float x
Those two simplifications are also applicable to UNSIGNED_FLOAT expression.
For example, compile the following code using aarch64-none-elf toolchain
with -O1 flag.
double
f1 (uint16_t x)
{
return (double)(float)x;
}
Before the change, the compiler generates the following code:
f1:
uxth w0, w0
ucvtf s0, w0
fcvt d0, s0
ret
After the change, the following simplified asm code snipts are generated.
f1:
uxth w0, w0
ucvtf d0, w0
ret
aarch64-none-elf regression test runs Okay. x86_64 bootstraps Okay.
Okay to commit?
gcc/ChangeLog:
2015-03-20 Renlin Li <renlin.li@arm.com>
* simplify-rtx.c (simplify_unary_operation_1): Fix a typo. Enable two
simplifications for UNSIGNED_FLOAT.
gcc/testsuite/ChangeLog:
2015-03-20 Renlin Li <renlin.li@arm.com>
* gcc.target/aarch64/unsigned-float.c: New.
* gcc.target/arm/unsigned-float.c: New.