[llvm-commits] [llvm] r155845 - /llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Mon Apr 30 15:19:00 2012
New Revision: 155845

URL: http://llvm.org/viewvc/llvm-project?rev=155845&view=rev
Log:
Fix address calculation error from r155744.

This was exposed by SingleSource/UnitTests/Vector/constpool.c.

The computed size of a basic block isn't always a multiple of its known
alignment, and that can introduce extra alignment padding after the
block.

<rdar://problem/11347135>

Modified:
    llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp

Modified: llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp?rev=155845&r1=155844&r2=155845&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMConstantIslandPass.cpp Mon Apr 30 15:19:00 2012
@@ -124,7 +124,12 @@
       /// This number should be used to predict worst case padding when
       /// splitting the block.
       unsigned internalKnownBits() const {
-        return Unalign ? Unalign : KnownBits;
+        unsigned Bits = Unalign ? Unalign : KnownBits;
+        // If the block size isn't a multiple of the known bits, assume the
+        // worst case padding.
+        if (Size & ((1u << Bits) - 1))
+          Bits = CountTrailingZeros_32(Size);
+        return Bits;
       }
 
       /// Compute the offset immediately following this block.  If LogAlign is