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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2012-07-11 18:31:59 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2012-07-11 18:31:59 +0000 |
| commit | 597f2950d8dc263f2264501200e390a92ebfb356 (patch) | |
| tree | 54625d38ecc000a872f69a28236026883caa92df /lib/Support/APInt.cpp | |
| parent | 79137851bf22d2181b56d060abde4398f36fc59c (diff) | |
| download | external_llvm-597f2950d8dc263f2264501200e390a92ebfb356.zip external_llvm-597f2950d8dc263f2264501200e390a92ebfb356.tar.gz external_llvm-597f2950d8dc263f2264501200e390a92ebfb356.tar.bz2 | |
PR13326: Fix a subtle edge case in the udiv -> magic multiply generator.
This caused 6 of 65k possible 8 bit udivs to be wrong.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160058 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Support/APInt.cpp')
| -rw-r--r-- | lib/Support/APInt.cpp | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp index 6a74883..38cfaed 100644 --- a/lib/Support/APInt.cpp +++ b/lib/Support/APInt.cpp @@ -1446,7 +1446,7 @@ APInt::mu APInt::magicu(unsigned LeadingZeros) const { APInt signedMin = APInt::getSignedMinValue(d.getBitWidth()); APInt signedMax = APInt::getSignedMaxValue(d.getBitWidth()); - nc = allOnes - (-d).urem(d); + nc = allOnes - (allOnes - d).urem(d); p = d.getBitWidth() - 1; // initialize p q1 = signedMin.udiv(nc); // initialize q1 = 2p/nc r1 = signedMin - q1*nc; // initialize r1 = rem(2p,nc) |