From: Nick Lewycky <nicholas@mxc.ca>
Date: Sun, 20 Sep 2009 04:27:06 +0000 (+0000)
Subject: Clean up the usage of evaluateICmpRelation's return value.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3892baac42daadf760d140168720be1d6e585aa8;p=oota-llvm.git

Clean up the usage of evaluateICmpRelation's return value.
Add another line to the ConstantExprFold test to demonstrate the GEPs may not
wrap around in either the signed or unsigned senses.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82361 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 773a908cf83..946ff5cd5f1 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -1263,7 +1263,7 @@ static ICmpInst::Predicate evaluateICmpRelation(LLVMContext &Context,
           else 
             // If its not weak linkage, the GVal must have a non-zero address
             // so the result is greater-than
-            return isSigned ? ICmpInst::ICMP_SGT :  ICmpInst::ICMP_UGT;
+            return isSigned ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT;
         } else if (isa<ConstantPointerNull>(CE1Op0)) {
           // If we are indexing from a null pointer, check to see if we have any
           // non-zero indices.
@@ -1567,64 +1567,57 @@ Constant *llvm::ConstantFoldCompareInstruction(LLVMContext &Context,
     case ICmpInst::ICMP_EQ:   // We know the constants are equal!
       // If we know the constants are equal, we can decide the result of this
       // computation precisely.
-      Result = (pred == ICmpInst::ICMP_EQ  ||
-                pred == ICmpInst::ICMP_ULE ||
-                pred == ICmpInst::ICMP_SLE ||
-                pred == ICmpInst::ICMP_UGE ||
-                pred == ICmpInst::ICMP_SGE);
+      Result = ICmpInst::isTrueWhenEqual((ICmpInst::Predicate)pred);
       break;
     case ICmpInst::ICMP_ULT:
-      // If we know that C1 < C2, we can decide the result of this computation
-      // precisely.
-      Result = (pred == ICmpInst::ICMP_ULT ||
-                pred == ICmpInst::ICMP_NE  ||
-                pred == ICmpInst::ICMP_ULE);
+      switch (pred) {
+      case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_ULE:
+	Result = 1; break;
+      case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_UGE:
+	Result = 0; break;
+      }
       break;
     case ICmpInst::ICMP_SLT:
-      // If we know that C1 < C2, we can decide the result of this computation
-      // precisely.
-      Result = (pred == ICmpInst::ICMP_SLT ||
-                pred == ICmpInst::ICMP_NE  ||
-                pred == ICmpInst::ICMP_SLE);
+      switch (pred) {
+      case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SLE:
+	Result = 1; break;
+      case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SGE:
+	Result = 0; break;
+      }
       break;
     case ICmpInst::ICMP_UGT:
-      // If we know that C1 > C2, we can decide the result of this computation
-      // precisely.
-      Result = (pred == ICmpInst::ICMP_UGT ||
-                pred == ICmpInst::ICMP_NE  ||
-                pred == ICmpInst::ICMP_UGE);
+      switch (pred) {
+      case ICmpInst::ICMP_UGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_UGE:
+	Result = 1; break;
+      case ICmpInst::ICMP_ULT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_ULE:
+	Result = 0; break;
+      }
       break;
     case ICmpInst::ICMP_SGT:
-      // If we know that C1 > C2, we can decide the result of this computation
-      // precisely.
-      Result = (pred == ICmpInst::ICMP_SGT ||
-                pred == ICmpInst::ICMP_NE  ||
-                pred == ICmpInst::ICMP_SGE);
+      switch (pred) {
+      case ICmpInst::ICMP_SGT: case ICmpInst::ICMP_NE: case ICmpInst::ICMP_SGE:
+	Result = 1; break;
+      case ICmpInst::ICMP_SLT: case ICmpInst::ICMP_EQ: case ICmpInst::ICMP_SLE:
+	Result = 0; break;
+      }
       break;
     case ICmpInst::ICMP_ULE:
-      // If we know that C1 <= C2, we can only partially decide this relation.
       if (pred == ICmpInst::ICMP_UGT) Result = 0;
-      if (pred == ICmpInst::ICMP_ULT) Result = 1;
+      if (pred == ICmpInst::ICMP_ULT || pred == ICmpInst::ICMP_ULE) Result = 1;
       break;
     case ICmpInst::ICMP_SLE:
-      // If we know that C1 <= C2, we can only partially decide this relation.
       if (pred == ICmpInst::ICMP_SGT) Result = 0;
-      if (pred == ICmpInst::ICMP_SLT) Result = 1;
+      if (pred == ICmpInst::ICMP_SLT || pred == ICmpInst::ICMP_SLE) Result = 1;
       break;
-
     case ICmpInst::ICMP_UGE:
-      // If we know that C1 >= C2, we can only partially decide this relation.
       if (pred == ICmpInst::ICMP_ULT) Result = 0;
-      if (pred == ICmpInst::ICMP_UGT) Result = 1;
+      if (pred == ICmpInst::ICMP_UGT || pred == ICmpInst::ICMP_UGE) Result = 1;
       break;
     case ICmpInst::ICMP_SGE:
-      // If we know that C1 >= C2, we can only partially decide this relation.
       if (pred == ICmpInst::ICMP_SLT) Result = 0;
-      if (pred == ICmpInst::ICMP_SGT) Result = 1;
+      if (pred == ICmpInst::ICMP_SGT || pred == ICmpInst::ICMP_SGE) Result = 1;
       break;
-
     case ICmpInst::ICMP_NE:
-      // If we know that C1 != C2, we can only partially decide this relation.
       if (pred == ICmpInst::ICMP_EQ) Result = 0;
       if (pred == ICmpInst::ICMP_NE) Result = 1;
       break;
diff --git a/test/Assembler/ConstantExprFold.ll b/test/Assembler/ConstantExprFold.ll
index 89edc24b37e..d3d374a07cf 100644
--- a/test/Assembler/ConstantExprFold.ll
+++ b/test/Assembler/ConstantExprFold.ll
@@ -19,6 +19,7 @@ global i64* inttoptr (i64 xor (i64 ptrtoint (i64* @A to i64), i64 0) to i64*) ;
 @B = external global %Ty 
 
 global i1 icmp slt (i64* @A, i64* getelementptr (i64* @A, i64 1))        ; true
+global i1 icmp ult (i64* @A, i64* getelementptr (i64* @A, i64 1))        ; true
 global i1 icmp slt (i64* @A, i64* getelementptr (i64* @A, i64 0))        ; false
 global i1 icmp slt (i32* getelementptr (%Ty* @B, i64 0, i32 0), 
                    i32* getelementptr (%Ty* @B, i64 0, i32 1))            ; true