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LoongArch: Redundant sign extension elimination optimization 2.

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Eliminate the redundant sign extension that exists after the conditional
move when the target register is SImode.

gcc/ChangeLog:

	* config/loongarch/loongarch.cc (loongarch_expand_conditional_move):
	Adjust.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/sign-extend-2.c: Adjust.
This commit is contained in:
Li Wei 2024-01-11 19:36:33 +08:00 • committed by Lulu Cheng
parent 493bebb3cd
commit ee005e72f5
2 changed files with 9 additions and 2 deletions
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6
gcc/config/loongarch/loongarch.cc
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@ -5371,6 +5371,12 @@ loongarch_expand_conditional_move (rtx *operands)
rtx temp3 = gen_reg_rtx (mode);
emit_insn (gen_rtx_SET (temp3, gen_rtx_IOR (mode, temp, temp2)));
temp3 = gen_lowpart (GET_MODE (operands[0]), temp3);
/* Nonzero in a subreg if it was made when accessing an object that
was promoted to a wider mode in accord with the PROMOTED_MODE
machine description macro. */
SUBREG_PROMOTED_VAR_P (temp3) = 1;
/* Sets promoted mode for SUBREG_PROMOTED_VAR_P. */
SUBREG_PROMOTED_SET (temp3, SRP_SIGNED);
loongarch_emit_move (operands[0], temp3);
}
else

5
gcc/testsuite/gcc.target/loongarch/sign-extend-2.c
View file

@ -1,6 +1,7 @@
/* { dg-do compile } */
/* { dg-options "-mabi=lp64d -O2" } */
/* { dg-final { scan-assembler-times "slli.w\t\\\$r\[0-9\]+,\\\$r\[0-9\]+,0" 1 } } */
/* { dg-options "-mabi=lp64d -O2 -fdump-rtl-expand" } */
/* { dg-final { scan-rtl-dump "subreg/s" "expand" } } */
/* { dg-final { scan-assembler-not "slli.w\t\\\$r\[0-9\]+,\\\$r\[0-9\]+,0" } } */
#include <stdint.h>
#define my_min(x, y) ((x) < (y) ? (x) : (y))