[LoopVectorizer] Predicate instructions in blocks with several incoming edges

We don't need to limit predication to blocks that have a single incoming
edge, we just need to use the right mask.
This fixes PR30172.

Differential Revision: https://reviews.llvm.org/D24009

llvm-svn: 280148

3 files changed, 66 insertions, 16 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 62b1339138f..3e57360cd23 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2930,12 +2930,8 @@ void InnerLoopVectorizer::scalarizeInstruction(Instruction *Instr,
   ScalarParts Entry(UF);
 
   VectorParts Cond;
-  if (IfPredicateInstr) {
-    assert(Instr->getParent()->getSinglePredecessor() &&
-           "Only support single predecessor blocks");
-    Cond = createEdgeMask(Instr->getParent()->getSinglePredecessor(),
-                          Instr->getParent());
-  }
+  if (IfPredicateInstr)
+    Cond = createBlockInMask(Instr->getParent());
 
   // For each vector unroll 'part':
   for (unsigned Part = 0; Part < UF; ++Part) {
@@ -6697,12 +6693,8 @@ void InnerLoopUnroller::scalarizeInstruction(Instruction *Instr,
   ScalarParts Entry(UF);
 
   VectorParts Cond;
-  if (IfPredicateInstr) {
-    assert(Instr->getParent()->getSinglePredecessor() &&
-           "Only support single predecessor blocks");
-    Cond = createEdgeMask(Instr->getParent()->getSinglePredecessor(),
-                          Instr->getParent());
-  }
+  if (IfPredicateInstr)
+    Cond = createBlockInMask(Instr->getParent());
 
   // For each vector unroll 'part':
   for (unsigned Part = 0; Part < UF; ++Part) {
diff --git a/llvm/test/Transforms/LoopVectorize/if-pred-non-void.ll b/llvm/test/Transforms/LoopVectorize/if-pred-non-void.ll
index 8e1f292650c..49ff437ba0a 100644
--- a/llvm/test/Transforms/LoopVectorize/if-pred-non-void.ll
+++ b/llvm/test/Transforms/LoopVectorize/if-pred-non-void.ll
@@ -153,3 +153,58 @@ if.end:                                           ; preds = %if.then, %for.body
   %exitcond = icmp eq i64 %indvars.iv.next, 128
   br i1 %exitcond, label %for.cond.cleanup, label %for.body
 }
+
+define void @pr30172(i32* nocapture %asd, i32* nocapture %bsd) {
+entry:
+  br label %for.body
+
+for.cond.cleanup:                                 ; preds = %if.end
+  ret void
+
+; CHECK-LABEL: pr30172
+; CHECK: vector.body:
+; CHECK: %[[CMP1:.+]] = icmp slt <2 x i32> %[[VAL:.+]], <i32 100, i32 100>
+; CHECK: %[[CMP2:.+]] = icmp sge <2 x i32> %[[VAL]], <i32 200, i32 200>
+; CHECK: %[[XOR:.+]] = xor <2 x i1> %[[CMP1]], <i1 true, i1 true>
+; CHECK: %[[AND1:.+]] = and <2 x i1> %[[XOR]], <i1 true, i1 true>
+; CHECK: %[[OR1:.+]] = or <2 x i1> zeroinitializer, %[[AND1]]
+; CHECK: %[[AND2:.+]] = and <2 x i1> %[[CMP2]], %[[OR1]]
+; CHECK: %[[OR2:.+]] = or <2 x i1> zeroinitializer, %[[AND2]]
+; CHECK: %[[AND3:.+]] = and <2 x i1> %[[CMP1]], <i1 true, i1 true>
+; CHECK: %[[OR3:.+]] = or <2 x i1> %[[OR2]], %[[AND3]]
+; CHECK: %[[EXTRACT:.+]] = extractelement <2 x i1> %[[OR3]], i32 0
+; CHECK: %[[MASK:.+]] = icmp eq i1 %[[EXTRACT]], true
+; CHECK: br i1 %[[MASK]], label %[[THEN:[a-zA-Z0-9.]+]], label %[[FI:[a-zA-Z0-9.]+]]
+; CHECK: [[THEN]]:
+; CHECK:   %[[PD:[a-zA-Z0-9]+]] = sdiv i32 %{{.*}}, %{{.*}}
+; CHECK:   br label %[[FI]]
+; CHECK: [[FI]]:
+; CHECK:   %{{.*}} = phi i32 [ undef, %vector.body ], [ %[[PD]], %[[THEN]] ]
+
+
+for.body:                                         ; preds = %if.end, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %if.end ]
+  %isd = getelementptr inbounds i32, i32* %asd, i64 %indvars.iv
+  %lsd = load i32, i32* %isd, align 4
+  %isd.b = getelementptr inbounds i32, i32* %bsd, i64 %indvars.iv
+  %lsd.b = load i32, i32* %isd.b, align 4
+  %psd = add nsw i32 %lsd, 23
+  %cmp1 = icmp slt i32 %lsd, 100
+  br i1 %cmp1, label %if.then, label %check
+
+check:                                            ; preds = %for.body
+  %cmp2 = icmp sge i32 %lsd, 200
+  br i1 %cmp2, label %if.then, label %if.end
+
+if.then:                                          ; preds = %check, %for.body
+  %sd1 = sdiv i32 %psd, %lsd
+  %rsd = sdiv i32 %lsd.b, %sd1
+  br label %if.end
+
+if.end:                                           ; preds = %if.then, %check
+  %ysd.0 = phi i32 [ %rsd, %if.then ], [ %psd, %check ] 
+  store i32 %ysd.0, i32* %isd, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 128
+  br i1 %exitcond, label %for.cond.cleanup, label %for.body
+}
diff --git a/llvm/test/Transforms/LoopVectorize/if-pred-stores.ll b/llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
index 91aa2d3f44f..766bbca6035 100644
--- a/llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
+++ b/llvm/test/Transforms/LoopVectorize/if-pred-stores.ll
@@ -18,7 +18,8 @@ entry:
 ; VEC:   %[[v8:.+]] = icmp sgt <2 x i32> %{{.*}}, <i32 100, i32 100>
 ; VEC:   %[[v9:.+]] = add nsw <2 x i32> %{{.*}}, <i32 20, i32 20>
 ; VEC:   %[[v10:.+]] = and <2 x i1> %[[v8]], <i1 true, i1 true>
-; VEC:   %[[v11:.+]] = extractelement <2 x i1> %[[v10]], i32 0
+; VEC:   %[[o1:.+]] = or <2 x i1> zeroinitializer, %[[v10]]
+; VEC:   %[[v11:.+]] = extractelement <2 x i1> %[[o1]], i32 0
 ; VEC:   %[[v12:.+]] = icmp eq i1 %[[v11]], true
 ; VEC:   br i1 %[[v12]], label %[[cond:.+]], label %[[else:.+]]
 ;
@@ -28,7 +29,7 @@ entry:
 ; VEC:   br label %[[else:.+]]
 ;
 ; VEC: [[else]]:
-; VEC:   %[[v15:.+]] = extractelement <2 x i1> %[[v10]], i32 1
+; VEC:   %[[v15:.+]] = extractelement <2 x i1> %[[o1]], i32 1
 ; VEC:   %[[v16:.+]] = icmp eq i1 %[[v15]], true
 ; VEC:   br i1 %[[v16]], label %[[cond2:.+]], label %[[else2:.+]]
 ;
@@ -51,7 +52,9 @@ entry:
 ; UNROLL:   %[[v5:[a-zA-Z0-9]+]] = icmp sgt i32 %[[v3]], 100
 ; UNROLL:   %[[v6:[a-zA-Z0-9]+]] = add nsw i32 %[[v2]], 20
 ; UNROLL:   %[[v7:[a-zA-Z0-9]+]] = add nsw i32 %[[v3]], 20
-; UNROLL:   %[[v8:[a-zA-Z0-9]+]] = icmp eq i1 %[[v4]], true
+; UNROLL:   %[[o1:[a-zA-Z0-9]+]] = or i1 false, %[[v4]]
+; UNROLL:   %[[o2:[a-zA-Z0-9]+]] = or i1 false, %[[v5]]
+; UNROLL:   %[[v8:[a-zA-Z0-9]+]] = icmp eq i1 %[[o1]], true
 ; UNROLL:   br i1 %[[v8]], label %[[cond:[a-zA-Z0-9.]+]], label %[[else:[a-zA-Z0-9.]+]]
 ;
 ; UNROLL: [[cond]]:
@@ -59,7 +62,7 @@ entry:
 ; UNROLL:   br label %[[else]]
 ;
 ; UNROLL: [[else]]:
-; UNROLL:   %[[v9:[a-zA-Z0-9]+]] = icmp eq i1 %[[v5]], true
+; UNROLL:   %[[v9:[a-zA-Z0-9]+]] = icmp eq i1 %[[o2]], true
 ; UNROLL:   br i1 %[[v9]], label %[[cond2:[a-zA-Z0-9.]+]], label %[[else2:[a-zA-Z0-9.]+]]
 ;
 ; UNROLL: [[cond2]]: