From: Nicolas Pitre <npitre@xxxxxxxxxxxx>
Let's use the same criteria for overflow handling necessity as the
generic code.
Signed-off-by: Nicolas Pitre <npitre@xxxxxxxxxxxx>
---
arch/arm/include/asm/div64.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h
index 4b69cf8504..562d5376ae 100644
--- a/arch/arm/include/asm/div64.h
+++ b/arch/arm/include/asm/div64.h
@@ -56,6 +56,8 @@ static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias)
{
unsigned long long res;
register unsigned int tmp asm("ip") = 0;
+ bool no_ovf = __builtin_constant_p(m) &&
+ ((m >> 32) + (m & 0xffffffff) < 0x100000000);
if (!bias) {
asm ( "umull %Q0, %R0, %Q1, %Q2\n\t"
@@ -63,7 +65,7 @@ static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias)
: "=&r" (res)
: "r" (m), "r" (n)
: "cc");
- } else if (!(m & ((1ULL << 63) | (1ULL << 31)))) {
+ } else if (no_ovf) {
res = m;
asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t"
"mov %Q0, #0"
@@ -80,7 +82,7 @@ static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias)
: "cc");
}
- if (!(m & ((1ULL << 63) | (1ULL << 31)))) {
+ if (no_ovf) {
asm ( "umlal %R0, %Q0, %R1, %Q2\n\t"
"umlal %R0, %Q0, %Q1, %R2\n\t"
"mov %R0, #0\n\t"
--
2.45.2
