在 2024/6/28 下午8:35, Xi Ruoyao 写道:
On Fri, 2024-06-28 at 20:34 +0800, chenglulu wrote:
在 2024/6/28 下午8:25, Xi Ruoyao 写道:
Hi Richard,
The late combine pass has triggered some FAILs on LoongArch and I'm
investigating. One of them is movcf2gr-via-fr.c. In
315r.postreload:
(insn 22 7 24 2 (set (reg:FCC 32 $f0 [87])
(reg:FCC 64 $fcc0 [87]))
"../gcc/gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c":9:12
168 {movfcc_internal}
(nil))
(insn 24 22 8 2 (set (reg:FCC 4 $r4 [88])
(reg:FCC 32 $f0 [87]))
"../gcc/gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c":9:12
168 {movfcc_internal}
(nil))
The late combine pass combines these to:
(insn 24 7 8 2 (set (reg:FCC 4 $r4 [88])
(reg:FCC 64 $fcc0 [87]))
"../gcc/gcc/testsuite/gcc.target/loongarch/movcf2gr-via-fr.c":9:12
168 {movfcc_internal}
(nil))
But we are using a FPR ($f0) here deliberately to work around an
architectural issue in LA464 causing a direct FCC-to-GPR move very
slow.
Could you suggest how to fix this issue?
Hi, Ruoyao:
We need to define TARGET_INSN_COST and set the cost of
movcf2gr/movgr2cf.
I've fixed this and am doing correctness testing now.
Ah thanks! So it uses insn cost instead of rtx cost and I didn't
realize.
That's right.:-D
