[llvm-commits] [llvm] r75444 - in /llvm/trunk: lib/Support/ConstantRange.cpp unittests/Support/ConstantRangeTest.cpp

[Nick Lewycky]

Author: nicholas
Date: Sun Jul 12 22:27:41 2009
New Revision: 75444

URL: http://llvm.org/viewvc/llvm-project?rev=75444&view=rev
Log:
Multiply was very wrong for wrapped ranges. This supplies a half-fix that will
generally return Full on all wrapped inputs. "Fixes" PR4545.

Modified:
    llvm/trunk/lib/Support/ConstantRange.cpp
    llvm/trunk/unittests/Support/ConstantRangeTest.cpp

Modified: llvm/trunk/lib/Support/ConstantRange.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/ConstantRange.cpp?rev=75444&r1=75443&r2=75444&view=diff

==============================================================================
--- llvm/trunk/lib/Support/ConstantRange.cpp (original)
+++ llvm/trunk/lib/Support/ConstantRange.cpp Sun Jul 12 22:27:41 2009
@@ -557,13 +557,13 @@
   if (isFullSet() || Other.isFullSet())
     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 
-  ConstantRange this_zext = zeroExtend(getBitWidth() * 2);
-  ConstantRange Other_zext = Other.zeroExtend(getBitWidth() * 2);
-
-  ConstantRange Result_zext = ConstantRange(
-      this_zext.getLower() * Other_zext.getLower(),
-      ((this_zext.getUpper()-1) * (Other_zext.getUpper()-1)) + 1);
+  APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
+  APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
+  APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
+  APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
 
+  ConstantRange Result_zext = ConstantRange(this_min * Other_min,
+                                            this_max * Other_max + 1);
   return Result_zext.truncate(getBitWidth());
 }
 

Modified: llvm/trunk/unittests/Support/ConstantRangeTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/ConstantRangeTest.cpp?rev=75444&r1=75443&r2=75444&view=diff

==============================================================================
--- llvm/trunk/unittests/Support/ConstantRangeTest.cpp (original)
+++ llvm/trunk/unittests/Support/ConstantRangeTest.cpp Sun Jul 12 22:27:41 2009
@@ -275,6 +275,11 @@
   EXPECT_TRUE(Some.multiply(Some).isFullSet());
   EXPECT_EQ(Some.multiply(Wrap), Full);
   EXPECT_EQ(Wrap.multiply(Wrap), Full);
+
+  // http://llvm.org/PR4545
+  EXPECT_EQ(ConstantRange(APInt(4, 1), APInt(4, 6)).multiply(
+              ConstantRange(APInt(4, 6), APInt(4, 2))),
+            ConstantRange(4, /*isFullSet=*/true));
 }
 
 TEST_F(ConstantRangeTest, UMax) {