[llvm] r252676 - [ValueTracking] Remove untested / unreachable code, NFC

[Sanjoy Das via llvm-commits]

Author: sanjoy
Date: Tue Nov 10 18:16:41 2015
New Revision: 252676

URL: http://llvm.org/viewvc/llvm-project?rev=252676&view=rev
Log:
[ValueTracking] Remove untested / unreachable code, NFC

Right now isTruePredicate is only ever called with Pred == ICMP_SLE or
ICMP_ULE, and the ICMP_SLT and ICMP_ULT cases are dead.  This change
removes the untested dead code so that the function is not misleading.

Modified:
    llvm/trunk/lib/Analysis/ValueTracking.cpp

Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=252676&r1=252675&r2=252676&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Tue Nov 10 18:16:41 2015
@@ -4111,31 +4111,21 @@ static bool isTruePredicate(CmpInst::Pre
   default:
     return false;
 
-  case CmpInst::ICMP_SLT:
   case CmpInst::ICMP_SLE: {
     const APInt *C;
 
-    // LHS s<  LHS +_{nsw} C   if C > 0
     // LHS s<= LHS +_{nsw} C   if C >= 0
-    if (match(RHS, m_NSWAdd(m_Specific(LHS), m_APInt(C)))) {
-      if (Pred == CmpInst::ICMP_SLT)
-        return C->isStrictlyPositive();
+    if (match(RHS, m_NSWAdd(m_Specific(LHS), m_APInt(C))))
       return !C->isNegative();
-    }
     return false;
   }
 
-  case CmpInst::ICMP_ULT:
   case CmpInst::ICMP_ULE: {
     const APInt *C;
 
-    // LHS u<  LHS +_{nuw} C   if C != 0
-    // LHS u<= LHS +_{nuw} C
-    if (match(RHS, m_NUWAdd(m_Specific(LHS), m_APInt(C)))) {
-      if (Pred == CmpInst::ICMP_ULT)
-        return C->isMinValue();
+    // LHS u<= LHS +_{nuw} C   for any C
+    if (match(RHS, m_NUWAdd(m_Specific(LHS), m_APInt(C))))
       return true;
-    }
 
     // Match A to (X +_{nuw} CA) and B to (X +_{nuw} CB)
     auto MatchNUWAddsToSameValue = [&](Value *A, Value *B, Value *&X,
@@ -4160,11 +4150,8 @@ static bool isTruePredicate(CmpInst::Pre
 
     Value *X;
     const APInt *CLHS, *CRHS;
-    if (MatchNUWAddsToSameValue(LHS, RHS, X, CLHS, CRHS)) {
-      if (Pred == CmpInst::ICMP_ULE)
-        return CLHS->ule(*CRHS);
-      return CLHS->ult(*CRHS);
-    }
+    if (MatchNUWAddsToSameValue(LHS, RHS, X, CLHS, CRHS))
+      return CLHS->ule(*CRHS);
 
     return false;
   }