[SLSR] use 'match' to simplify code; NFC

This pass could probably be modified slightly to allow
vector splat transforms for practically no cost, but
it only works on scalars for now. So the use of the
newer 'match' API should make no functional difference. 

llvm-svn: 345030

2 files changed, 34 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
index 2061db13639..b5089b006bd 100644
--- a/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
@@ -640,12 +640,12 @@ void StraightLineStrengthReduce::rewriteCandidateWithBasis(
   Value *Reduced = nullptr; // equivalent to but weaker than C.Ins
   switch (C.CandidateKind) {
   case Candidate::Add:
-  case Candidate::Mul:
+  case Candidate::Mul: {
     // C = Basis + Bump
-    if (BinaryOperator::isNeg(Bump)) {
+    Value *NegBump;
+    if (match(Bump, m_Neg(m_Value(NegBump)))) {
       // If Bump is a neg instruction, emit C = Basis - (-Bump).
-      Reduced =
-          Builder.CreateSub(Basis.Ins, BinaryOperator::getNegArgument(Bump));
+      Reduced = Builder.CreateSub(Basis.Ins, NegBump);
       // We only use the negative argument of Bump, and Bump itself may be
       // trivially dead.
       RecursivelyDeleteTriviallyDeadInstructions(Bump);
@@ -662,6 +662,7 @@ void StraightLineStrengthReduce::rewriteCandidateWithBasis(
       Reduced = Builder.CreateAdd(Basis.Ins, Bump);
     }
     break;
+  }
   case Candidate::GEP:
     {
       Type *IntPtrTy = DL->getIntPtrType(C.Ins->getType());
diff --git a/llvm/test/Transforms/StraightLineStrengthReduce/slsr-add.ll b/llvm/test/Transforms/StraightLineStrengthReduce/slsr-add.ll
index c3bffb270af..92af617dab8 100644
--- a/llvm/test/Transforms/StraightLineStrengthReduce/slsr-add.ll
+++ b/llvm/test/Transforms/StraightLineStrengthReduce/slsr-add.ll
@@ -99,6 +99,34 @@ define void @stride_is_minus_2s(i32 %b, i32 %s) {
   ret void
 }
 
+; TODO: This pass is targeted at simple address-calcs, so it is artificially limited to
+; match scalar values. The code could be modified to handle vector types too.
+
+define void @stride_is_minus_2s_vec(<2 x i32> %b, <2 x i32> %s) {
+; CHECK-LABEL: @stride_is_minus_2s_vec(
+; CHECK-NEXT:    [[S6:%.*]] = mul <2 x i32> [[S:%.*]], <i32 6, i32 6>
+; CHECK-NEXT:    [[T1:%.*]] = add <2 x i32> [[B:%.*]], [[S6]]
+; CHECK-NEXT:    call void @voo(<2 x i32> [[T1]])
+; CHECK-NEXT:    [[S4:%.*]] = shl <2 x i32> [[S]], <i32 2, i32 2>
+; CHECK-NEXT:    [[T2:%.*]] = add <2 x i32> [[B]], [[S4]]
+; CHECK-NEXT:    call void @voo(<2 x i32> [[T2]])
+; CHECK-NEXT:    [[S2:%.*]] = shl <2 x i32> [[S]], <i32 1, i32 1>
+; CHECK-NEXT:    [[T3:%.*]] = add <2 x i32> [[B]], [[S2]]
+; CHECK-NEXT:    call void @voo(<2 x i32> [[T3]])
+; CHECK-NEXT:    ret void
+;
+  %s6 = mul <2 x i32> %s, <i32 6, i32 6>
+  %t1 = add <2 x i32> %b, %s6
+  call void @voo(<2 x i32> %t1)
+  %s4 = shl <2 x i32> %s, <i32 2, i32 2>
+  %t2 = add <2 x i32> %b, %s4
+  call void @voo(<2 x i32> %t2)
+  %s2 = shl <2 x i32> %s, <i32 1, i32 1>
+  %t3 = add <2 x i32> %b, %s2
+  call void @voo(<2 x i32> %t3)
+  ret void
+}
+
 ; t = b + (s << 3);
 ; foo(t);
 ; foo(b + s);
@@ -140,4 +168,5 @@ define void @slsr_strided_add_128bit(i128 %b, i128 %s) {
 }
 
 declare void @foo(i32)
+declare void @voo(<2 x i32>)
 declare void @bar(i128)