[InstSimplify][InstCombine] Modify the interface of decomposeBitTestICmp and use it in the InstSimplify

This addresses a fixme in InstSimplify about using decomposeBitTest. This also fixes InstSimplify to handle ugt and ult compares too.

I've modified the interface a little to return only the APInt version of the mask that InstSimplify needs. InstCombine now has a small wrapper routine to create a Constant out of it. I've also dropped the returning of 0 since InstSimplify doesn't need that. So InstCombine creates a zero constant itself.

I also had to make decomposeBitTest support vectors since InstSimplify needs that.

As InstSimplify can't use something from the Transforms library, I've moved the CmpInstAnalysis code to the Analysis library.

Differential Revision: https://reviews.llvm.org/D36593

llvm-svn: 310869

1 files changed, 15 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index dfc2ea3e4de..dc5b5bfefe6 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -12,11 +12,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "InstCombineInternal.h"
+#include "llvm/Analysis/CmpInstAnalysis.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/PatternMatch.h"
-#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 using namespace PatternMatch;
@@ -292,6 +292,18 @@ static unsigned conjugateICmpMask(unsigned Mask) {
   return NewMask;
 }
 
+// Adapts the external decomposeBitTestICmp for local use.
+static bool decomposeBitTestICmp(Value *LHS, Value *RHS, CmpInst::Predicate &Pred,
+                                 Value *&X, Value *&Y, Value *&Z) {
+  APInt Mask;
+  if (!llvm::decomposeBitTestICmp(LHS, RHS, Pred, X, Mask))
+    return false;
+
+  Y = ConstantInt::get(X->getType(), Mask);
+  Z = ConstantInt::get(X->getType(), 0);
+  return true;
+}
+
 /// Handle (icmp(A & B) ==/!= C) &/| (icmp(A & D) ==/!= E).
 /// Return the set of pattern classes (from MaskedICmpType) that both LHS and
 /// RHS satisfy.
@@ -316,7 +328,7 @@ static unsigned getMaskedTypeForICmpPair(Value *&A, Value *&B, Value *&C,
   Value *L2 = LHS->getOperand(1);
   Value *L11, *L12, *L21, *L22;
   // Check whether the icmp can be decomposed into a bit test.
-  if (decomposeBitTestICmp(LHS, PredL, L11, L12, L2)) {
+  if (decomposeBitTestICmp(L1, L2, PredL, L11, L12, L2)) {
     L21 = L22 = L1 = nullptr;
   } else {
     // Look for ANDs in the LHS icmp.
@@ -347,7 +359,7 @@ static unsigned getMaskedTypeForICmpPair(Value *&A, Value *&B, Value *&C,
   Value *R2 = RHS->getOperand(1);
   Value *R11, *R12;
   bool Ok = false;
-  if (decomposeBitTestICmp(RHS, PredR, R11, R12, R2)) {
+  if (decomposeBitTestICmp(R1, R2, PredR, R11, R12, R2)) {
     if (R11 == L11 || R11 == L12 || R11 == L21 || R11 == L22) {
       A = R11;
       D = R12;