a73ffa2206
(This is the third attempt to check in this patch, and the first two are r255454 and r255460. The once failed test file reg-usage.ll is now moved to test/Transform/LoopVectorize/X86 directory with target datalayout and target triple indicated.) LoopVectorizationCostModel::calculateRegisterUsage() is used to estimate the register usage for specific VFs. However, it takes into account many instructions that won't be vectorized, such as induction variables, GetElementPtr instruction, etc.. This makes the loop vectorizer too conservative when choosing VF. In this patch, the induction variables that won't be vectorized plus GetElementPtr instruction will be added to ValuesToIgnore set so that their register usage won't be considered any more. Differential revision: http://reviews.llvm.org/D15177 llvm-svn: 255691
72 lines
2.4 KiB
LLVM
72 lines
2.4 KiB
LLVM
; RUN: opt < %s -debug-only=loop-vectorize -loop-vectorize -vectorizer-maximize-bandwidth -O2 -S 2>&1 | FileCheck %s
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; REQUIRES: asserts
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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"
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target triple = "x86_64-unknown-linux-gnu"
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@a = global [1024 x i8] zeroinitializer, align 16
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@b = global [1024 x i8] zeroinitializer, align 16
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define i32 @foo() {
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; This function has a loop of SAD pattern. Here we check when VF = 16 the
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; register usage doesn't exceed 16.
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;
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; CHECK-LABEL: foo
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; CHECK: LV(REG): VF = 4
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; CHECK-NEXT: LV(REG): Found max usage: 4
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; CHECK: LV(REG): VF = 8
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; CHECK-NEXT: LV(REG): Found max usage: 7
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; CHECK: LV(REG): VF = 16
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; CHECK-NEXT: LV(REG): Found max usage: 13
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entry:
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br label %for.body
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for.cond.cleanup:
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%add.lcssa = phi i32 [ %add, %for.body ]
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ret i32 %add.lcssa
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for.body:
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%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
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%s.015 = phi i32 [ 0, %entry ], [ %add, %for.body ]
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%arrayidx = getelementptr inbounds [1024 x i8], [1024 x i8]* @a, i64 0, i64 %indvars.iv
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%0 = load i8, i8* %arrayidx, align 1
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%conv = zext i8 %0 to i32
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%arrayidx2 = getelementptr inbounds [1024 x i8], [1024 x i8]* @b, i64 0, i64 %indvars.iv
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%1 = load i8, i8* %arrayidx2, align 1
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%conv3 = zext i8 %1 to i32
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%sub = sub nsw i32 %conv, %conv3
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%ispos = icmp sgt i32 %sub, -1
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%neg = sub nsw i32 0, %sub
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%2 = select i1 %ispos, i32 %sub, i32 %neg
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%add = add nsw i32 %2, %s.015
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%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
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%exitcond = icmp eq i64 %indvars.iv.next, 1024
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br i1 %exitcond, label %for.cond.cleanup, label %for.body
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}
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define i64 @bar(i64* nocapture %a) {
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; CHECK-LABEL: bar
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; CHECK: LV(REG): VF = 2
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; CHECK: LV(REG): Found max usage: 4
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;
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entry:
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br label %for.body
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for.cond.cleanup:
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%add2.lcssa = phi i64 [ %add2, %for.body ]
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ret i64 %add2.lcssa
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for.body:
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%i.012 = phi i64 [ 0, %entry ], [ %inc, %for.body ]
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%s.011 = phi i64 [ 0, %entry ], [ %add2, %for.body ]
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%arrayidx = getelementptr inbounds i64, i64* %a, i64 %i.012
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%0 = load i64, i64* %arrayidx, align 8
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%add = add nsw i64 %0, %i.012
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store i64 %add, i64* %arrayidx, align 8
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%add2 = add nsw i64 %add, %s.011
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%inc = add nuw nsw i64 %i.012, 1
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%exitcond = icmp eq i64 %inc, 1024
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br i1 %exitcond, label %for.cond.cleanup, label %for.body
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}
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