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[vectorizer] Add an override for the target instruction cost and use it 

to stabilize a test that really is trying to test generic behavior and
not a specific target's behavior.

llvm-svn: 200215
This commit is contained in:
Chandler Carruth 2014-01-27 11:41:50 +00:00
parent 2bb03ba605
commit edfa37effa
2 changed files with 12 additions and 1 deletions
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11
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
View File

@ -160,6 +160,12 @@ static cl::opt<unsigned> ForceTargetMaxVectorUnrollFactor(
cl::desc("A flag that overrides the target's max unroll factor for " cl::desc("A flag that overrides the target's max unroll factor for "
"vectorized loops.")); "vectorized loops."));
static cl::opt<unsigned> ForceTargetInstructionCost(
"force-target-instruction-cost", cl::init(0), cl::Hidden,
cl::desc("A flag that overrides the target's expected cost for "
"an instruction to a single constant value. Mostly "
"useful for getting consistent testing."));
static cl::opt<unsigned> SmallLoopCost( static cl::opt<unsigned> SmallLoopCost(
"small-loop-cost", cl::init(20), cl::Hidden, "small-loop-cost", cl::init(20), cl::Hidden,
cl::desc("The cost of a loop that is considered 'small' by the unroller.")); cl::desc("The cost of a loop that is considered 'small' by the unroller."));
@ -5185,6 +5191,11 @@ unsigned LoopVectorizationCostModel::expectedCost(unsigned VF) {
continue; continue;
unsigned C = getInstructionCost(it, VF); unsigned C = getInstructionCost(it, VF);
// Check if we should override the cost.
if (ForceTargetInstructionCost.getNumOccurrences() > 0)
C = ForceTargetInstructionCost;
BlockCost += C; BlockCost += C;
DEBUG(dbgs() << "LV: Found an estimated cost of " << C << " for VF " << DEBUG(dbgs() << "LV: Found an estimated cost of " << C << " for VF " <<
VF << " For instruction: " << *it << '\n'); VF << " For instruction: " << *it << '\n');

2
llvm/test/Transforms/LoopVectorize/unroll_novec.ll
View File

@ -1,4 +1,4 @@
; RUN: opt < %s -loop-vectorize -force-vector-width=1 -force-target-num-scalar-regs=16 -force-target-max-scalar-unroll=8 -small-loop-cost=20 -dce -instcombine -S | FileCheck %s ; RUN: opt < %s -loop-vectorize -force-vector-width=1 -force-target-num-scalar-regs=16 -force-target-max-scalar-unroll=8 -force-target-instruction-cost=1 -small-loop-cost=40 -dce -instcombine -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.8.0" target triple = "x86_64-apple-macosx10.8.0"