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31123d4529
of operations that provably don't overflow. For example, we can prove
%civ.inc below does not sign-overflow. With this change,
IndVarSimplify changes %civ.inc to an add nsw.
define i32 @foo(i32* %array, i32* %length_ptr, i32 %init) {
entry:
%length = load i32* %length_ptr, !range !0
%len.sub.1 = sub i32 %length, 1
%upper = icmp slt i32 %init, %len.sub.1
br i1 %upper, label %loop, label %exit
loop:
%civ = phi i32 [ %init, %entry ], [ %civ.inc, %latch ]
%civ.inc = add i32 %civ, 1
%cmp = icmp slt i32 %civ.inc, %length
br i1 %cmp, label %latch, label %break
latch:
store i32 0, i32* %array
%check = icmp slt i32 %civ.inc, %len.sub.1
br i1 %check, label %loop, label %break
break:
ret i32 %civ.inc
exit:
ret i32 42
}
Differential Revision: http://reviews.llvm.org/D6748
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225282 91177308-0d34-0410-b5e6-96231b3b80d8
44 lines
1.5 KiB
LLVM
44 lines
1.5 KiB
LLVM
; RUN: opt < %s -indvars -S | FileCheck %s
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; Test WidenIV::GetExtendedOperandRecurrence.
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; %add, %sub and %mul should be extended to i64 because it is nsw, even though its
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; sext cannot be hoisted outside the loop.
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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"
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define void @test() nounwind {
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entry:
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br i1 undef, label %for.body11, label %for.end285
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for.body11: ; preds = %entry
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%shl = shl i32 1, 1
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%shl132 = shl i32 %shl, 1
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br label %for.body153
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for.body153: ; preds = %for.body153, %for.body11
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br i1 undef, label %for.body170, label %for.body153
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; CHECK: add nuw nsw i64 %indvars.iv, 1
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; CHECK: sub nsw i64 %indvars.iv, 2
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; CHECK: sub nsw i64 4, %indvars.iv
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; CHECK: mul nsw i64 %indvars.iv, 8
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for.body170: ; preds = %for.body170, %for.body153
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%i2.19 = phi i32 [ %add249, %for.body170 ], [ 0, %for.body153 ]
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%add = add nsw i32 %i2.19, 1
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%add.idxprom = sext i32 %add to i64
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%sub = sub nsw i32 %i2.19, 2
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%sub.idxprom = sext i32 %sub to i64
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%sub.neg = sub nsw i32 4, %i2.19
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%sub.neg.idxprom = sext i32 %sub.neg to i64
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%mul = mul nsw i32 %i2.19, 8
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%mul.idxprom = sext i32 %mul to i64
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%add249 = add nsw i32 %i2.19, %shl132
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br label %for.body170
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for.end285: ; preds = %entry
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ret void
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}
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