Eliminate an assortment of undefined behavior.

Hopefully, this fixes the PPC64 buildbots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185218 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2013-06-28 21:10:25 +00:00
parent 4025fa5b85
commit e187512bde

View File

@ -47,9 +47,13 @@ static uint64_t div96bit(uint64_t W[2], uint32_t D) {
uint64_t x = W[1];
unsigned i;
// This is really a 64-bit division.
if (!x)
return y / D;
// This long division algorithm automatically saturates on overflow.
for (i = 0; i < 64 && x; ++i) {
uint32_t t = (int)x >> 31;
uint32_t t = -((x >> 31) & 1); // Splat bit 31 to bits 0-31.
x = (x << 1) | (y >> 63);
y = y << 1;
if ((x | t) >= D) {