[InstCombine] use m_APInt to allow demanded bits analysis on splat constants

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294628 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index fb7177f1ddbd8c88de463ee449f1eb19b2618c3a..42ce76b7cc24a9b431b9b77fa20a3f4ba7b154b5 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -30,18 +30,20 @@ static bool ShrinkDemandedConstant(Instruction *I, unsigned OpNo,
   assert(I && "No instruction?");
   assert(OpNo < I->getNumOperands() && "Operand index too large");
 
-  // If the operand is not a constant integer, nothing to do.
-  ConstantInt *OpC = dyn_cast<ConstantInt>(I->getOperand(OpNo));
-  if (!OpC) return false;
+  // The operand must be a constant integer or splat integer.
+  Value *Op = I->getOperand(OpNo);
+  const APInt *C;
+  if (!match(Op, m_APInt(C)))
+    return false;
 
   // If there are no bits set that aren't demanded, nothing to do.
-  Demanded = Demanded.zextOrTrunc(OpC->getValue().getBitWidth());
-  if ((~Demanded & OpC->getValue()) == 0)
+  Demanded = Demanded.zextOrTrunc(C->getBitWidth());
+  if ((~Demanded & *C) == 0)
     return false;
 
   // This instruction is producing bits that are not demanded. Shrink the RHS.
-  Demanded &= OpC->getValue();
-  I->setOperand(OpNo, ConstantInt::get(OpC->getType(), Demanded));
+  Demanded &= *C;
+  I->setOperand(OpNo, ConstantInt::get(Op->getType(), Demanded));
 
   return true;
 }
@@ -114,9 +116,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
       KnownOne.getBitWidth() == BitWidth &&
       "Value *V, DemandedMask, KnownZero and KnownOne "
       "must have same BitWidth");
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
-    // We know all of the bits for a constant!
-    KnownOne = CI->getValue() & DemandedMask;
+  const APInt *C;
+  if (match(V, m_APInt(C))) {
+    // We know all of the bits for a scalar constant or a splat vector constant!
+    KnownOne = *C & DemandedMask;
     KnownZero = ~KnownOne & DemandedMask;
     return nullptr;
   }

diff --git a/test/Transforms/InstCombine/and.ll b/test/Transforms/InstCombine/and.ll
index 40f5cf271362159cca87c0105a0ca2e1d6245552..b433574974a94ddcc0ba19268350efcea2f1579d 100644 (file)
--- a/test/Transforms/InstCombine/and.ll
+++ b/test/Transforms/InstCombine/and.ll
@@ -382,12 +382,11 @@ define i32 @test31(i1 %X) {
   ret i32 %A
 }
 
-; FIXME: Demanded bit analysis allows us to eliminate the add.
+; Demanded bit analysis allows us to eliminate the add.
 
 define <2 x i32> @and_demanded_bits_splat_vec(<2 x i32> %x) {
 ; CHECK-LABEL: @and_demanded_bits_splat_vec(
-; CHECK-NEXT:    [[Y:%.*]] = add <2 x i32> %x, <i32 8, i32 8>
-; CHECK-NEXT:    [[Z:%.*]] = and <2 x i32> [[Y]], <i32 7, i32 7>
+; CHECK-NEXT:    [[Z:%.*]] = and <2 x i32> %x, <i32 7, i32 7>
 ; CHECK-NEXT:    ret <2 x i32> [[Z]]
 ;
   %y = add <2 x i32> %x, <i32 8, i32 8>

diff --git a/test/Transforms/InstCombine/zext.ll b/test/Transforms/InstCombine/zext.ll
index 740509809d1c4a2fb0e1fa0ce778d796cc6ed454..887d839cb8c79d5426fcce2a0c10aab7873522ef 100644 (file)
--- a/test/Transforms/InstCombine/zext.ll
+++ b/test/Transforms/InstCombine/zext.ll
@@ -35,7 +35,7 @@ define <2 x i64> @test3(<2 x i64> %A) {
 
 define <2 x i64> @test4(<2 x i64> %A) {
 ; CHECK-LABEL: @test4(
-; CHECK-NEXT:    [[TMP1:%.*]] = xor <2 x i64> %A, <i64 4294967295, i64 4294967295>
+; CHECK-NEXT:    [[TMP1:%.*]] = xor <2 x i64> %A, <i64 63, i64 63>
 ; CHECK-NEXT:    [[XOR:%.*]] = and <2 x i64> [[TMP1]], <i64 23, i64 42>
 ; CHECK-NEXT:    ret <2 x i64> [[XOR]]
 ;