[llvm-branch-commits] [llvm-branch] r339985 - Merging r339515:

[Hans Wennborg via llvm-branch-commits]

Author: hans
Date: Fri Aug 17 00:04:47 2018
New Revision: 339985

URL: http://llvm.org/viewvc/llvm-project?rev=339985&view=rev
Log:
Merging r339515:
------------------------------------------------------------------------
r339515 | d0k | 2018-08-12 13:43:03 +0200 (Sun, 12 Aug 2018) | 4 lines

[InstSimplify] Guard against large shift amounts.

These are always UB, but can happen for large integer inputs. Testing it
is very fragile as -simplifycfg will nuke the UB top-down.
------------------------------------------------------------------------

Modified:
    llvm/branches/release_70/   (props changed)
    llvm/branches/release_70/lib/Analysis/InstructionSimplify.cpp

Propchange: llvm/branches/release_70/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Fri Aug 17 00:04:47 2018
@@ -1,3 +1,3 @@
 /llvm/branches/Apple/Pertwee:110850,110961
 /llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155241,338552,338554,338569,338599,338610,338658,338665,338682,338703,338709,338716,338751,338762,338817,338902,338915,338968,339073,339166,339179,339184,339190,339225,339316,339319,339411,339492,339533,339535-339536,339600,339636,339769
+/llvm/trunk:155241,338552,338554,338569,338599,338610,338658,338665,338682,338703,338709,338716,338751,338762,338817,338902,338915,338968,339073,339166,339179,339184,339190,339225,339316,339319,339411,339492,339515,339533,339535-339536,339600,339636,339769

Modified: llvm/branches/release_70/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_70/lib/Analysis/InstructionSimplify.cpp?rev=339985&r1=339984&r2=339985&view=diff
==============================================================================
--- llvm/branches/release_70/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/branches/release_70/lib/Analysis/InstructionSimplify.cpp Fri Aug 17 00:04:47 2018
@@ -1338,7 +1338,7 @@ static Value *SimplifyLShrInst(Value *Op
     const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
     const unsigned Width = Op0->getType()->getScalarSizeInBits();
     const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
-    if (EffWidthY <= ShRAmt->getZExtValue())
+    if (ShRAmt->uge(EffWidthY))
       return X;
   }
 
@@ -1878,9 +1878,9 @@ static Value *SimplifyAndInst(Value *Op0
       match(Op0, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X), m_APInt(ShAmt)),
                                      m_Value(XShifted)),
                         m_Value(Y)))) {
-    const unsigned ShftCnt = ShAmt->getZExtValue();
-    const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
     const unsigned Width = Op0->getType()->getScalarSizeInBits();
+    const unsigned ShftCnt = ShAmt->getLimitedValue(Width);
+    const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
     const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
     if (EffWidthY <= ShftCnt) {
       const KnownBits XKnown = computeKnownBits(X, Q.DL, 0, Q.AC, Q.CxtI,