ExtractValue instruction costs

Instruction ExtractValue wasn't handled in
LoopVectorizationCostModel::getInstructionCost(). As a result, it was modeled
as a mul which is not really accurate. Since it is free (most of the times),
this now gets a cost of 0 using getInstructionCost.

This is a follow-up of D92208, that required changing this regression test.
In a follow up I will look at InsertValue which also isn't handled yet.

Differential Revision: https://reviews.llvm.org/D92317

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index ce4f57f..d389e03 100644 (file)
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -6853,6 +6853,8 @@ unsigned LoopVectorizationCostModel::getInstructionCost(Instruction *I,
       return std::min(CallCost, getVectorIntrinsicCost(CI, VF));
     return CallCost;
   }
+  case Instruction::ExtractValue:
+    return TTI.getInstructionCost(I, TTI::TCK_RecipThroughput);
   default:
     // The cost of executing VF copies of the scalar instruction. This opcode
     // is unknown. Assume that it is the same as 'mul'.

diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll b/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll
index 37c1f4e..35c2ddb 100644 (file)
--- a/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/extractvalue-no-scalarization-required.ll
@@ -8,9 +8,9 @@
 ; Check scalar cost for extractvalue. The constant and loop invariant operands are free,
 ; leaving cost 3 for scalarizing the result + 2 for executing the op with VF 2.
 
-; CM: LV: Scalar loop costs: 7.
-; CM: LV: Found an estimated cost of 19 for VF 2 For instruction:   %a = extractvalue { i64, i64 } %sv, 0
-; CM-NEXT: LV: Found an estimated cost of 19 for VF 2 For instruction:   %b = extractvalue { i64, i64 } %sv, 1
+; CM: LV: Scalar loop costs: 5.
+; CM: LV: Found an estimated cost of 0 for VF 2 For instruction:   %a = extractvalue { i64, i64 } %sv, 0
+; CM-NEXT: LV: Found an estimated cost of 0 for VF 2 For instruction:   %b = extractvalue { i64, i64 } %sv, 1
 
 ; Check that the extractvalue operands are actually free in vector code.
 
@@ -57,9 +57,9 @@ exit:
 ; Similar to the test case above, but checks getVectorCallCost as well.
 declare float @pow(float, float) readnone nounwind
 
-; CM: LV: Scalar loop costs: 16.
-; CM: LV: Found an estimated cost of 5 for VF 2 For instruction:   %a = extractvalue { float, float } %sv, 0
-; CM-NEXT: LV: Found an estimated cost of 5 for VF 2 For instruction:   %b = extractvalue { float, float } %sv, 1
+; CM: LV: Scalar loop costs: 14.
+; CM: LV: Found an estimated cost of 0 for VF 2 For instruction:   %a = extractvalue { float, float } %sv, 0
+; CM-NEXT: LV: Found an estimated cost of 0 for VF 2 For instruction:   %b = extractvalue { float, float } %sv, 1
 
 ; FORCED-LABEL: define void @test_getVectorCallCost
 
@@ -101,6 +101,3 @@ loop.body:
 exit:
   ret void
 }
-
-
-