[llvm-commits] [llvm] r128203 - /llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp

[Evan Cheng]

Author: evancheng
Date: Thu Mar 24 01:20:03 2011
New Revision: 128203

URL: http://llvm.org/viewvc/llvm-project?rev=128203&view=rev
Log:
Nasty bug in ARMBaseInstrInfo::produceSameValue(). The MachineConstantPoolEntry
entries being compared may not be ARMConstantPoolValue. Without checking
whether they are ARMConstantPoolValue first, and if the stars and moons
are aligned properly, the equality test may return true (when the first few
words of two Constants' values happen to be identical) and very bad things can
happen.

rdar://9125354

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

Modified: llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp?rev=128203&r1=128202&r2=128203&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseInstrInfo.cpp Thu Mar 24 01:20:03 2011
@@ -1080,11 +1080,18 @@
     int CPI1 = MO1.getIndex();
     const MachineConstantPoolEntry &MCPE0 = MCP->getConstants()[CPI0];
     const MachineConstantPoolEntry &MCPE1 = MCP->getConstants()[CPI1];
-    ARMConstantPoolValue *ACPV0 =
-      static_cast<ARMConstantPoolValue*>(MCPE0.Val.MachineCPVal);
-    ARMConstantPoolValue *ACPV1 =
-      static_cast<ARMConstantPoolValue*>(MCPE1.Val.MachineCPVal);
-    return ACPV0->hasSameValue(ACPV1);
+    bool isARMCP0 = MCPE0.isMachineConstantPoolEntry();
+    bool isARMCP1 = MCPE1.isMachineConstantPoolEntry();
+    if (isARMCP0 && isARMCP1) {
+      ARMConstantPoolValue *ACPV0 =
+        static_cast<ARMConstantPoolValue*>(MCPE0.Val.MachineCPVal);
+      ARMConstantPoolValue *ACPV1 =
+        static_cast<ARMConstantPoolValue*>(MCPE1.Val.MachineCPVal);
+      return ACPV0->hasSameValue(ACPV1);
+    } else if (!isARMCP0 && !isARMCP1) {
+      return MCPE0.Val.ConstVal == MCPE1.Val.ConstVal;
+    }
+    return false;
   } else if (Opcode == ARM::PICLDR) {
     if (MI1->getOpcode() != Opcode)
       return false;