https://gcc.gnu.org/g:34ae3a992a0cc3240d07d69ff12a664cbb5c8be0
commit r15-4173-g34ae3a992a0cc3240d07d69ff12a664cbb5c8be0
Author: Palmer Dabbelt <pal...@rivosinc.com>
Date: Tue Oct 8 07:28:32 2024 -0600
[RISC-V][PR target/116615] RISC-V: Use default LOGICAL_OP_NON_SHORT_CIRCUIT
> We have cheap logical ops, so let's just move this back to the default
> to take advantage of the standard branch/op hueristics.
>
> gcc/ChangeLog:
>
> PR target/116615
> * config/riscv/riscv.h (LOGICAL_OP_NON_SHORT_CIRCUIT): Remove.
> ---
> There's a bunch more discussion in the bug, but it's starting to smell
> like this was just a holdover from MIPS (where maybe it also shouldn't
> be set). I haven't tested this, but I figured I'd send the patch to get
> a little more visibility.
>
> I guess we should also kick off something like a SPEC run to make sure
> there's no regressions?
So as I noted earlier, this appears to be a nice win on the BPI. Testsuite
fallout is minimal -- just the one SFB related test tripping at -Os that was
also hit by Andrew P's work.
After looking at it more closely, the SFB codegen and the codegen after
Andrew's work should be equivalent assuming two independent ops can dispatch
together.
The test actually generates sensible code at -Os. It's the -Os in
combination
with the -fno-ssa-phiopt that causes problems. I think the best thing to
do
here is just skip at -Os. That still keeps a degree of testing the SFB
path.
Tested successfully in my tester. But will wait for the pre-commit tester
to
render a verdict before moving forward.
PR target/116615
gcc/
* config/riscv/riscv.h (LOGICAL_OP_NON_SHORT_CIRCUIT): Remove.
gcc/testsuite/
* gcc.target/riscv/cset-sext-sfb.c: Skip for -Os.
Co-authored-by: Jeff Law <j...@ventanamicro.com>
Diff:
---
gcc/config/riscv/riscv.h | 2 --
gcc/testsuite/gcc.target/riscv/cset-sext-sfb.c | 2 +-
2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 3aecb43f8312..53b7b2a40ed9 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -939,8 +939,6 @@ extern enum riscv_cc get_riscv_cc (const rtx use);
#define TARGET_VECTOR_MISALIGN_SUPPORTED \
riscv_vector_unaligned_access_p
-#define LOGICAL_OP_NON_SHORT_CIRCUIT 0
-
/* Control the assembler format that we output. */
/* Output to assembler file text saying following lines
diff --git a/gcc/testsuite/gcc.target/riscv/cset-sext-sfb.c
b/gcc/testsuite/gcc.target/riscv/cset-sext-sfb.c
index 6e9f8cc61de0..1ee45b33e152 100644
--- a/gcc/testsuite/gcc.target/riscv/cset-sext-sfb.c
+++ b/gcc/testsuite/gcc.target/riscv/cset-sext-sfb.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-O1" } } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" "-O1" "-Os" } } */
/* { dg-options "-march=rv32gc -mtune=sifive-7-series -mbranch-cost=1
-fno-ssa-phiopt -fdump-rtl-ce1" { target { rv32 } } } */
/* { dg-options "-march=rv64gc -mtune=sifive-7-series -mbranch-cost=1
-fno-ssa-phiopt -fdump-rtl-ce1" { target { rv64 } } } */
