https://gcc.gnu.org/g:d102db7194a3e30b9544724dd09b84de2fcfb0f7
commit r16-4949-gd102db7194a3e30b9544724dd09b84de2fcfb0f7 Author: Guo Jie <[email protected]> Date: Sat Nov 1 15:33:06 2025 +0800 LoongArch: Correct the cost of mulh.{w[u]/d[u]} gcc/ChangeLog: * config/loongarch/loongarch.cc (loongarch_rtx_costs): Correct the cost of mulh.{w[u]|d[u]}. gcc/testsuite/ChangeLog: * gcc.target/loongarch/mulh_wu.c: New test. Diff: --- gcc/config/loongarch/loongarch.cc | 27 ++++++++++++++++++++++++++- gcc/testsuite/gcc.target/loongarch/mulh_wu.c | 10 ++++++++++ 2 files changed, 36 insertions(+), 1 deletion(-) diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc index c725d028d8c3..735753ad7e2d 100644 --- a/gcc/config/loongarch/loongarch.cc +++ b/gcc/config/loongarch/loongarch.cc @@ -3978,9 +3978,34 @@ loongarch_rtx_costs (rtx x, machine_mode mode, int outer_code, speed); return true; + case LSHIFTRT: + /* Correct the cost of mulh.{w[u]/d[u]}. */ + if (outer_code == TRUNCATE && CONST_INT_P (XEXP (x, 1)) + && INTVAL (XEXP (x, 1)) == (GET_MODE_BITSIZE (mode) / 2) + && GET_CODE (XEXP (x, 0)) == MULT + && ((GET_CODE (XEXP (XEXP (x, 0), 0)) == ZERO_EXTEND + && GET_CODE (XEXP (XEXP (x, 0), 1)) == ZERO_EXTEND) + || (GET_CODE (XEXP (XEXP (x, 0), 0)) == SIGN_EXTEND + && GET_CODE (XEXP (XEXP (x, 0), 1)) == SIGN_EXTEND)) + && GET_CODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == REG + && GET_CODE (XEXP (XEXP (XEXP (x, 0), 1), 0)) == REG) + { + if (GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == SImode + && GET_MODE (XEXP (XEXP (XEXP (x, 0), 1), 0)) == SImode) + { + *total = loongarch_cost->int_mult_si; + return true; + } + if (GET_MODE (XEXP (XEXP (XEXP (x, 0), 0), 0)) == DImode + && GET_MODE (XEXP (XEXP (XEXP (x, 0), 1), 0)) == DImode) + { + *total = loongarch_cost->int_mult_di; + return true; + } + } + /* Fall through. */ case ASHIFT: case ASHIFTRT: - case LSHIFTRT: case ROTATE: case ROTATERT: if (CONSTANT_P (XEXP (x, 1))) diff --git a/gcc/testsuite/gcc.target/loongarch/mulh_wu.c b/gcc/testsuite/gcc.target/loongarch/mulh_wu.c new file mode 100644 index 000000000000..53fc518313c5 --- /dev/null +++ b/gcc/testsuite/gcc.target/loongarch/mulh_wu.c @@ -0,0 +1,10 @@ +/* { dg-do compile { target { loongarch64*-*-* } } } */ +/* { dg-options "-O3 -mabi=lp64d" } */ +/* { dg-final { scan-assembler "\tmulh.wu" } } */ +/* { dg-final { scan-assembler-not "\tlu32i.d" } } */ + +unsigned int +test (unsigned int *a) +{ + return *a / 60; +}
