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| author | liuhongt <hongtao.liu@intel.com> | 2024-02-19 13:57:24 +0800 |
|---|---|---|
| committer | liuhongt <hongtao.liu@intel.com> | 2024-05-29 06:59:15 +0800 |
| commit | 1d6199e5f8c1c08083eeb0279f71333234fe14ad (patch) | |
| tree | 3a28592bbec190fda9cec69c17c5ad225340b6d6 | |
| parent | 6f36cc2535c11b9406715836daeb87169fa79473 (diff) | |
| download | gcc-1d6199e5f8c1c08083eeb0279f71333234fe14ad.zip gcc-1d6199e5f8c1c08083eeb0279f71333234fe14ad.tar.gz gcc-1d6199e5f8c1c08083eeb0279f71333234fe14ad.tar.bz2 | |
Reduce cost of MEM (A + imm).
For MEM, rtx_cost iterates each subrtx, and adds up the costs,
so for MEM (reg) and MEM (reg + 4), the former costs 5,
the latter costs 9, it is not accurate for x86. Ideally
address_cost should be used, but it reduce cost too much.
So current solution is make constant disp as cheap as possible.
gcc/ChangeLog:
PR target/67325
* config/i386/i386.cc (ix86_rtx_costs): Reduce cost of MEM (A
+ imm) to "cost of MEM (A)" + 1.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr67325.c: New test.
| -rw-r--r-- | gcc/config/i386/i386.cc | 18 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr67325.c | 7 |
2 files changed, 24 insertions, 1 deletions
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc index 3e2a3a1..85d87b9 100644 --- a/gcc/config/i386/i386.cc +++ b/gcc/config/i386/i386.cc @@ -22194,7 +22194,23 @@ ix86_rtx_costs (rtx x, machine_mode mode, int outer_code_i, int opno, /* An insn that accesses memory is slightly more expensive than one that does not. */ if (speed) - *total += 1; + { + *total += 1; + rtx addr = XEXP (x, 0); + /* For MEM, rtx_cost iterates each subrtx, and adds up the costs, + so for MEM (reg) and MEM (reg + 4), the former costs 5, + the latter costs 9, it is not accurate for x86. Ideally + address_cost should be used, but it reduce cost too much. + So current solution is make constant disp as cheap as possible. */ + if (GET_CODE (addr) == PLUS + && x86_64_immediate_operand (XEXP (addr, 1), Pmode)) + { + *total += 1; + *total += rtx_cost (XEXP (addr, 0), Pmode, PLUS, 0, speed); + return true; + } + } + return false; case ZERO_EXTRACT: diff --git a/gcc/testsuite/gcc.target/i386/pr67325.c b/gcc/testsuite/gcc.target/i386/pr67325.c new file mode 100644 index 0000000..c3c1e4c --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr67325.c @@ -0,0 +1,7 @@ +/* { dg-do compile { target { ! ia32 } } } */ +/* { dg-options "-O2" } */ +/* { dg-final { scan-assembler-not "(?:sar|shr)" } } */ + +int f(long*l){ + return *l>>32; +} |