From: Vineet Gupta <vineetg@rivosinc.com>
To: gcc-patches@gcc.gnu.org
Cc: kito.cheng@gmail.com, Jeff Law <jeffreyalaw@gmail.com>,
Palmer Dabbelt <palmer@rivosinc.com>,
Christoph Mullner <christoph.muellner@vrull.eu>,
gnu-toolchain@rivosinc.com, Vineet Gupta <vineetg@rivosinc.com>
Subject: [PATCH] RISC-V: improve codegen for large constants with same 32-bit lo and hi parts [2]
Date: Thu, 18 May 2023 13:57:16 -0700 [thread overview]
Message-ID: <20230518205716.3258223-1-vineetg@rivosinc.com> (raw)
[part #2 of PR/109279]
SPEC2017 deepsjeng uses large constants which currently generates less than
ideal code. This fix improves codegen for large constants which have
same low and hi parts: e.g.
long long f(void) { return 0x0101010101010101ull; }
Before
li a5,0x1010000
addi a5,a5,0x101
mv a0,a5
slli a5,a5,32
add a0,a5,a0
ret
With patch
li a5,0x1010000
addi a5,a5,0x101
slli a0,a5,32
add a0,a0,a5
ret
This is testsuite clean.
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_split_integer): if loval is equal
to hival, ASHIFT the corresponding regs.
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
---
gcc/config/riscv/riscv.cc | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 79122699b6f5..4e1bb2f14cf8 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -703,13 +703,18 @@ riscv_split_integer (HOST_WIDE_INT val, machine_mode mode)
unsigned HOST_WIDE_INT hival = sext_hwi ((val - loval) >> 32, 32);
rtx hi = gen_reg_rtx (mode), lo = gen_reg_rtx (mode);
- riscv_move_integer (hi, hi, hival, mode);
riscv_move_integer (lo, lo, loval, mode);
- hi = gen_rtx_fmt_ee (ASHIFT, mode, hi, GEN_INT (32));
- hi = force_reg (mode, hi);
+ if (loval == hival)
+ hi = gen_rtx_ASHIFT (mode, lo, GEN_INT (32));
+ else
+ {
+ riscv_move_integer (hi, hi, hival, mode);
+ hi = gen_rtx_ASHIFT (mode, hi, GEN_INT (32));
+ }
- return gen_rtx_fmt_ee (PLUS, mode, hi, lo);
+ hi = force_reg (mode, hi);
+ return gen_rtx_PLUS (mode, hi, lo);
}
/* Return true if X is a thread-local symbol. */
--
2.34.1
next reply other threads:[~2023-05-18 20:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-18 20:57 Vineet Gupta [this message]
2023-05-19 16:33 ` Jeff Law
2023-05-19 16:36 ` Palmer Dabbelt
2023-05-19 17:21 ` Vineet Gupta
2023-05-19 17:21 ` [Committed] " Vineet Gupta
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