Re: [PATCH v3] LoongArch: Define LOGICAL_OP_NON_SHORT_CIRCUIT

[chenglulu <chenglulu@loongson.cn>]

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Hi, Jiahao:

This patch will introduce redundant FAIL, and the reason needs to be explained.

+FAIL: gcc.dg/tree-ssa/copy-headers-8.c scan-tree-dump-times ch2 "Conditional combines static and invariant" 1
+FAIL: gcc.dg/tree-ssa/copy-headers-8.c scan-tree-dump-times ch2 "Will duplicate bb" 2
+FAIL: gcc.dg/tree-ssa/update-threading.c scan-tree-dump-times optimized "Invalid sum" 0

在 2024/1/16 上午10:32, Jiahao Xu 写道:
> Define LOGICAL_OP_NON_SHORT_CIRCUIT as 0, for a short-circuit branch, use the
> short-circuit operation instead of the non-short-circuit operation.
>
> SPEC2017 performance evaluation shows 1% performance improvement for fprate
> GEOMEAN and no obvious regression for others. Especially, 526.blender_r +10.6%
> on 3A6000.
>
> gcc/ChangeLog:
>
> 	* config/loongarch/loongarch.h (LOGICAL_OP_NON_SHORT_CIRCUIT): Define.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/loongarch/short-circuit.c: New test.
>
> diff --git a/gcc/config/loongarch/loongarch.h b/gcc/config/loongarch/loongarch.h
> index 4e6ede926d3..8b453ab3140 100644
> --- a/gcc/config/loongarch/loongarch.h
> +++ b/gcc/config/loongarch/loongarch.h
> @@ -869,6 +869,7 @@ typedef struct {
>      1 is the default; other values are interpreted relative to that.  */
>   
>   #define BRANCH_COST(speed_p, predictable_p) la_branch_cost
> +#define LOGICAL_OP_NON_SHORT_CIRCUIT 0
>   
>   /* Return the asm template for a conditional branch instruction.
>      OPCODE is the opcode's mnemonic and OPERANDS is the asm template for
> diff --git a/gcc/testsuite/gcc.target/loongarch/short-circuit.c b/gcc/testsuite/gcc.target/loongarch/short-circuit.c
> new file mode 100644
> index 00000000000..bed585ee172
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/loongarch/short-circuit.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -ffast-math -fdump-tree-gimple" } */
> +
> +int
> +short_circuit (float *a)
> +{
> +  float t1x = a[0];
> +  float t2x = a[1];
> +  float t1y = a[2];
> +  float t2y = a[3];
> +  float t1z = a[4];
> +  float t2z = a[5];
> +
> +  if (t1x > t2y  || t2x < t1y  || t1x > t2z || t2x < t1z || t1y > t2z || t2y < t1z)
> +    return 0;
> +
> +  return 1;
> +}
> +/* { dg-final { scan-tree-dump-times "if" 6 "gimple" } } */