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llvm-mirror/test/Transforms/LoopVectorize/induction.ll
Arnold Schwaighofer fba1c74b67 LoopVectorizer: Perform redundancy elimination on induction variables
When the loop vectorizer was part of the SCC inliner pass manager gvn would
run after the loop vectorizer followed by instcombine. This way redundancy
(multiple uses) were removed and instcombine could perform scalarization on the
induction variables. Having moved the loop vectorizer to later we no longer run
any form of redundancy elimination before we perform instcombine. This caused
vectorized induction variables to survive that did not before.

On a recent iMac this helps linpack back from 6000Mflops to 7000Mflops.

This should also help lpbench and paq8p.

I ran a Release (without Asserts) build over the test-suite and did not see any
negative impact on compile time.

radar://15339680

llvm-svn: 193891
2013-11-01 22:18:19 +00:00

69 lines
2.5 KiB
LLVM

; RUN: opt < %s -loop-vectorize -force-vector-unroll=1 -force-vector-width=2 -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"
; Make sure that we can handle multiple integer induction variables.
; CHECK-LABEL: @multi_int_induction(
; CHECK: vector.body:
; CHECK: %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
; CHECK: %normalized.idx = sub i64 %index, 0
; CHECK: %[[VAR:.*]] = trunc i64 %normalized.idx to i32
; CHECK: %offset.idx = add i32 190, %[[VAR]]
define void @multi_int_induction(i32* %A, i32 %N) {
for.body.lr.ph:
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
%count.09 = phi i32 [ 190, %for.body.lr.ph ], [ %inc, %for.body ]
%arrayidx2 = getelementptr inbounds i32* %A, i64 %indvars.iv
store i32 %count.09, i32* %arrayidx2, align 4
%inc = add nsw i32 %count.09, 1
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp ne i32 %lftr.wideiv, %N
br i1 %exitcond, label %for.body, label %for.end
for.end:
ret void
}
; RUN: opt < %s -loop-vectorize -force-vector-unroll=1 -force-vector-width=2 -instcombine -S | FileCheck %s --check-prefix=IND
; Make sure we remove unneeded vectorization of induction variables.
; In order for instcombine to cleanup the vectorized induction variables that we
; create in the loop vectorizer we need to perform some form of redundancy
; elimination to get rid of multiple uses.
; IND-LABEL: scalar_use
; IND: br label %vector.body
; IND: vector.body:
; Vectorized induction variable.
; IND-NOT: insertelement <2 x i64>
; IND-NOT: shufflevector <2 x i64>
; IND: br {{.*}}, label %vector.body
define void @scalar_use(float* %a, float %b, i64 %offset, i64 %offset2, i64 %n) {
entry:
br label %for.body
for.body:
%iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
%ind.sum = add i64 %iv, %offset
%arr.idx = getelementptr inbounds float* %a, i64 %ind.sum
%l1 = load float* %arr.idx, align 4
%ind.sum2 = add i64 %iv, %offset2
%arr.idx2 = getelementptr inbounds float* %a, i64 %ind.sum2
%l2 = load float* %arr.idx2, align 4
%m = fmul fast float %b, %l2
%ad = fadd fast float %l1, %m
store float %ad, float* %arr.idx, align 4
%iv.next = add nuw nsw i64 %iv, 1
%exitcond = icmp eq i64 %iv.next, %n
br i1 %exitcond, label %loopexit, label %for.body
loopexit:
ret void
}