From e187512bde9fd090a78924928a0b8793e3d87cbb Mon Sep 17 00:00:00 2001 From: Jakob Stoklund Olesen Date: Fri, 28 Jun 2013 21:10:25 +0000 Subject: [PATCH] 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 --- lib/Support/BlockFrequency.cpp | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/lib/Support/BlockFrequency.cpp b/lib/Support/BlockFrequency.cpp index 6e4d6b1b33c..8de517fad64 100644 --- a/lib/Support/BlockFrequency.cpp +++ b/lib/Support/BlockFrequency.cpp @@ -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) { -- 2.34.1