[LV] Remove induction recipes only used outside vector loop.

Exit values of vector inductions are generated completely independent of
the induction recipes. Consider them for removal, if they are not used
in loop.

This fixes a crash exposed by 49b23f451cf7130.

diff --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 5e8e91b..90fdb69 100644 (file)
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -368,9 +368,12 @@ void VPlanTransforms::removeDeadRecipes(VPlan &Plan, Loop &OrigLoop) {
     if (R.mayHaveSideEffects() ||
         any_of(R.definedValues(),
                [](VPValue *V) { return V->getNumUsers() > 0; }) ||
-        (R.getUnderlyingInstr() &&
+        (R.getUnderlyingInstr() && !isa<VPWidenIntOrFpInductionRecipe>(&R) &&
          any_of(R.getUnderlyingInstr()->users(), [&OrigLoop](User *U) {
            // Check for live-out users currently not modeled in VPlan.
+           // Note that exit values of VPWidenIntOrFpInductionRecipes are
+           // generated independent of the recipe. Such recipes can be removed,
+           // independent of uses outside the loop.
            // TODO: Remove once live-outs are modeled in VPlan.
            return !OrigLoop.contains(cast<Instruction>(U));
          })))

diff --git a/llvm/test/Transforms/LoopVectorize/iv_outside_user.ll b/llvm/test/Transforms/LoopVectorize/iv_outside_user.ll
index 373aa9b..fb96e4a 100644 (file)
--- a/llvm/test/Transforms/LoopVectorize/iv_outside_user.ll
+++ b/llvm/test/Transforms/LoopVectorize/iv_outside_user.ll
@@ -1,5 +1,5 @@
 ; RUN: opt -S -loop-vectorize -force-vector-interleave=1 -force-vector-width=2 < %s | FileCheck --check-prefixes=CHECK,VEC %s
-; RUN: opt -S -loop-vectorize -force-vector-interleave=2 -force-vector-width=1 < %s | FileCheck --check-prefixes=CHECK,INTERLEAVE %s
+; RUN: opt -S -loop-vectorize -force-vector-interleave=2 -force-vector-width=1 < %s | FileCheck --check-prefixes=CHECK %s
 
 ; CHECK-LABEL: @postinc
 ; CHECK-LABEL: scalar.ph:
@@ -208,12 +208,7 @@ define i32 @iv_2_dead_in_loop_only_used_outside(i64* %ptr) {
 ; VEC-NEXT:     [[VEC_IND:%.+]] = phi <2 x i64> [ <i64 0, i64 1>, %vector.ph ], [ [[VEC_IND_NEXT:%.+]], %vector.body ]
 ; CHECK-NEXT:   [[IV_0:%.+]] = add i64 [[INDEX]], 0
 ; CHECK-NEXT:   [[IV_1:%.+]] = add i64 [[INDEX]], 1
-; CHECK-NEXT:   [[INDEX_TRUNC:%.+]] = trunc i64 [[INDEX]] to i32
-; CHECK-NEXT:   [[IV_2_OFFSET:%.+]] = mul i32 [[INDEX_TRUNC]], 2
-; CHECK-NEXT:   [[IV_2_0:%.+]] = add i32 %offset.idx, 0
-; INTERLEAVE-NEXT: [[IV_2_1:%.+]] = add i32 %offset.idx, 2
-; CHECK-NOT:    [[IV_2_0]]
-; INTERLEAVE-NOT:  [[IV_2_1]]
+; CHECK-NOT:    [[IV_2_0:%.+]] = add i32 %offset.idx, 0
 ; CHECK-LABEL: scalar.ph:
 ; CHECK-NEXT:    {{.+}} = phi i64 [ 1002, %middle.block ], [ 0, %entry ]
 ; CHECK-NEXT:    {{.+}} = phi i32 [ 2004, %middle.block ], [ 0, %entry ]