From 4013baf99c38f7bca06a51f8301e8fb195ccfa33 Mon Sep 17 00:00:00 2001 From: Jim Wilson Date: Tue, 2 Jun 2020 11:19:39 -0700 Subject: [PATCH] RISC-V: Make __divdi3 handle div by zero same as hardware. The ISA manual specifies that divide by zero always returns -1 as the result. We were failing to do that when the dividend was negative. Original patch from Virginie Moser. libgcc/ * config/riscv/div.S (__divdi3): For negative arguments, change bgez to bgtz. --- libgcc/config/riscv/div.S | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/libgcc/config/riscv/div.S b/libgcc/config/riscv/div.S index 151f8e273ac..17234324c1e 100644 --- a/libgcc/config/riscv/div.S +++ b/libgcc/config/riscv/div.S @@ -107,10 +107,12 @@ FUNC_END (__umoddi3) /* Handle negative arguments to __divdi3. */ .L10: neg a0, a0 - bgez a1, .L12 /* Compute __udivdi3(-a0, a1), then negate the result. */ + /* Zero is handled as a negative so that the result will not be inverted. */ + bgtz a1, .L12 /* Compute __udivdi3(-a0, a1), then negate the result. */ + neg a1, a1 - j __udivdi3 /* Compute __udivdi3(-a0, -a1). */ -.L11: /* Compute __udivdi3(a0, -a1), then negate the result. */ + j __udivdi3 /* Compute __udivdi3(-a0, -a1). */ +.L11: /* Compute __udivdi3(a0, -a1), then negate the result. */ neg a1, a1 .L12: move t0, ra