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https://github.com/c64scene-ar/llvm-6502.git
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8cff277de2
In a case where we have a no {un,}signed wrap flag on the increment, if
RHS - Start is constant then we can avoid inserting a max operation bewteen
the two, since we can statically determine which is greater.
This allows us to unroll loops such as:
void testcase3(int v) {
for (int i=v; i<=v+1; ++i)
f(i);
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220960 91177308-0d34-0410-b5e6-96231b3b80d8
33 lines
692 B
LLVM
33 lines
692 B
LLVM
; RUN: opt -loop-unroll -S %s | FileCheck %s
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; extern void f(int);
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; void test1(int v) {
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; for (int i=v; i<=v+1; ++i)
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; f(i);
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; }
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;
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; We can use the nsw information to see that the tripcount will be 2, so the
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; loop should be unrolled as this is always beneficial
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declare void @f(i32)
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; CHECK-LABEL: @test1
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define void @test1(i32 %v) {
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entry:
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%add = add nsw i32 %v, 1
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br label %for.body
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for.body:
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%i.04 = phi i32 [ %v, %entry ], [ %inc, %for.body ]
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tail call void @f(i32 %i.04)
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%inc = add nsw i32 %i.04, 1
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%cmp = icmp slt i32 %i.04, %add
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br i1 %cmp, label %for.body, label %for.end
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; CHECK: call void @f
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; CHECK-NOT: br i1
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; CHECK: call void @f
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for.end:
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ret void
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}
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