[llvm] r320463 - [LV] Ignore the cost of values that will not appear in the vectorized loop
Dorit Nuzman via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 12 00:57:43 PST 2017
Author: dorit
Date: Tue Dec 12 00:57:43 2017
New Revision: 320463
URL: http://llvm.org/viewvc/llvm-project?rev=320463&view=rev
Log:
[LV] Ignore the cost of values that will not appear in the vectorized loop
VecValuesToIgnore holds values that will not appear in the vectorized loop.
We should therefore ignore their cost when VF > 1.
Differential Revision: https://reviews.llvm.org/D40883
Added:
llvm/trunk/test/Transforms/LoopVectorize/X86/reduction-small-size.ll
Modified:
llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=320463&r1=320462&r2=320463&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Tue Dec 12 00:57:43 2017
@@ -6877,7 +6877,8 @@ LoopVectorizationCostModel::expectedCost
continue;
// Skip ignored values.
- if (ValuesToIgnore.count(&I))
+ if (ValuesToIgnore.count(&I) ||
+ (VF > 1 && VecValuesToIgnore.count(&I)))
continue;
VectorizationCostTy C = getInstructionCost(&I, VF);
Added: llvm/trunk/test/Transforms/LoopVectorize/X86/reduction-small-size.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopVectorize/X86/reduction-small-size.ll?rev=320463&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopVectorize/X86/reduction-small-size.ll (added)
+++ llvm/trunk/test/Transforms/LoopVectorize/X86/reduction-small-size.ll Tue Dec 12 00:57:43 2017
@@ -0,0 +1,80 @@
+; REQUIRES: asserts
+; RUN: opt < %s -loop-vectorize -mcpu=core-axv2 -force-vector-interleave=1 -dce -instcombine -debug-only=loop-vectorize -S < %s 2>&1 | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+; Make sure we ignore the costs of the redundant reduction casts
+; char reduction_i8(char *a, char *b, int n) {
+; char sum = 0;
+; for (int i = 0; i < n; ++i)
+; sum += (a[i] + b[i]);
+; return sum;
+; }
+;
+
+; CHECK-LABEL: reduction_i8
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = phi
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = phi
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = getelementptr
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = load
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = zext i8 %{{.*}} to i32
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = getelementptr
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = load
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = zext i8 %{{.*}} to i32
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = and i32 %{{.*}}, 255
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = add
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = add
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = add
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = trunc
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: %{{.*}} = icmp
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 1 For instruction: br
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = phi
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = phi
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = getelementptr
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = load
+; CHECK-NOT: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = zext i8 %{{.*}} to i32
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = getelementptr
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = load
+; CHECK-NOT: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = zext i8 %{{.*}} to i32
+; CHECK-NOT: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = and i32 %{{.*}}, 255
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = add
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = add
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = add
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = trunc
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: %{{.*}} = icmp
+; CHECK: LV: Found an estimated cost of {{[0-9]+}} for VF 2 For instruction: br
+;
+define i8 @reduction_i8(i8* nocapture readonly %a, i8* nocapture readonly %b, i32 %n) {
+entry:
+ %cmp.12 = icmp sgt i32 %n, 0
+ br i1 %cmp.12, label %for.body.preheader, label %for.cond.cleanup
+
+for.body.preheader:
+ br label %for.body
+
+for.cond.for.cond.cleanup_crit_edge:
+ %add5.lcssa = phi i32 [ %add5, %for.body ]
+ %conv6 = trunc i32 %add5.lcssa to i8
+ br label %for.cond.cleanup
+
+for.cond.cleanup:
+ %sum.0.lcssa = phi i8 [ %conv6, %for.cond.for.cond.cleanup_crit_edge ], [ 0, %entry ]
+ ret i8 %sum.0.lcssa
+
+for.body:
+ %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
+ %sum.013 = phi i32 [ %add5, %for.body ], [ 0, %for.body.preheader ]
+ %arrayidx = getelementptr inbounds i8, i8* %a, i64 %indvars.iv
+ %0 = load i8, i8* %arrayidx, align 1
+ %conv = zext i8 %0 to i32
+ %arrayidx2 = getelementptr inbounds i8, i8* %b, i64 %indvars.iv
+ %1 = load i8, i8* %arrayidx2, align 1
+ %conv3 = zext i8 %1 to i32
+ %conv4 = and i32 %sum.013, 255
+ %add = add nuw nsw i32 %conv, %conv4
+ %add5 = add nuw nsw i32 %add, %conv3
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+ %exitcond = icmp eq i32 %lftr.wideiv, %n
+ br i1 %exitcond, label %for.cond.for.cond.cleanup_crit_edge, label %for.body
+}
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