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llvm-6502/test/Transforms/IndVarSimplify/ult-sub-to-eq.ll

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Teach SCEV's icmp simplification logic that a-b == 0 is equivalent to a == b. This also required making recursive simplifications until nothing changes or a hard limit (currently 3) is hit. With the simplification in place indvars can canonicalize loops of the form for (unsigned i = 0; i < a-b; ++i) into for (unsigned i = 0; i != a-b; ++i) which used to fail because SCEV created a weird umax expr for the backedge taken count. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157701 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-30 18:32:23 +00:00
; RUN: opt -S -indvars < %s | FileCheck %s
define void @test1(float* nocapture %autoc, float* nocapture %data, float %d, i32 %data_len, i32 %sample) nounwind {
entry:
%sub = sub i32 %data_len, %sample
%cmp4 = icmp eq i32 %data_len, %sample
br i1 %cmp4, label %for.end, label %for.body
for.body: ; preds = %entry, %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
%0 = trunc i64 %indvars.iv to i32
%add = add i32 %0, %sample
%idxprom = zext i32 %add to i64
%arrayidx = getelementptr inbounds float* %data, i64 %idxprom
%1 = load float* %arrayidx, align 4
%mul = fmul float %1, %d
%arrayidx2 = getelementptr inbounds float* %autoc, i64 %indvars.iv
%2 = load float* %arrayidx2, align 4
%add3 = fadd float %2, %mul
store float %add3, float* %arrayidx2, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%3 = trunc i64 %indvars.iv.next to i32
%cmp = icmp ult i32 %3, %sub
br i1 %cmp, label %for.body, label %for.end
for.end: ; preds = %for.body, %entry
ret void
Update Transforms tests to use CHECK-LABEL for easier debugging. No functionality change. This update was done with the following bash script: find test/Transforms -name "*.ll" | \ while read NAME; do echo "$NAME" if ! grep -q "^; *RUN: *llc" $NAME; then TEMP=`mktemp -t temp` cp $NAME $TEMP sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \ while read FUNC; do sed -i '' "s/;\(.*\)\([A-Za-z0-9_]*\):\( *\)@$FUNC\([( ]*\)\$/;\1\2-LABEL:\3@$FUNC(/g" $TEMP done mv $TEMP $NAME fi done git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186268 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-14 01:42:54 +00:00
; CHECK-LABEL: @test1(
Teach SCEV's icmp simplification logic that a-b == 0 is equivalent to a == b. This also required making recursive simplifications until nothing changes or a hard limit (currently 3) is hit. With the simplification in place indvars can canonicalize loops of the form for (unsigned i = 0; i < a-b; ++i) into for (unsigned i = 0; i != a-b; ++i) which used to fail because SCEV created a weird umax expr for the backedge taken count. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157701 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-30 18:32:23 +00:00
; First check that we move the sub into the preheader, it doesn't have to be
; executed if %cmp4 == false
; CHECK: for.body.preheader:
; CHECK: sub i32 %data_len, %sample
; CHECK: br label %for.body
; Second, check that we turn the IV test into an eq.
; CHECK: %lftr.wideiv = trunc i64 %indvars.iv.next to i32
; CHECK: %exitcond = icmp ne i32 %lftr.wideiv, %0
; CHECK: br i1 %exitcond, label %for.body, label %for.end.loopexit
}
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