mirror of
https://github.com/c64scene-ar/llvm-6502.git
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fdefc694cd
Splitting a loop to make range checks redundant is profitable only if the range check "never" fails. Make this fact a part of recognizing a range check -- a branch is a range check only if it is expected to pass (via branch_weights metadata). Differential Revision: http://reviews.llvm.org/D7192 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227249 91177308-0d34-0410-b5e6-96231b3b80d8
61 lines
1.9 KiB
LLVM
61 lines
1.9 KiB
LLVM
; RUN: opt -irce -S < %s | FileCheck %s
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define void @multiple_access_no_preloop(
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i32* %arr_a, i32* %a_len_ptr, i32* %arr_b, i32* %b_len_ptr, i32 %n) {
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entry:
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%len.a = load i32* %a_len_ptr, !range !0
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%len.b = load i32* %b_len_ptr, !range !0
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%first.itr.check = icmp sgt i32 %n, 0
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br i1 %first.itr.check, label %loop, label %exit
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loop:
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%idx = phi i32 [ 0, %entry ] , [ %idx.next, %in.bounds.b ]
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%idx.next = add i32 %idx, 1
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%abc.a = icmp slt i32 %idx, %len.a
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br i1 %abc.a, label %in.bounds.a, label %out.of.bounds, !prof !1
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in.bounds.a:
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%addr.a = getelementptr i32* %arr_a, i32 %idx
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store i32 0, i32* %addr.a
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%abc.b = icmp slt i32 %idx, %len.b
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br i1 %abc.b, label %in.bounds.b, label %out.of.bounds, !prof !1
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in.bounds.b:
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%addr.b = getelementptr i32* %arr_b, i32 %idx
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store i32 -1, i32* %addr.b
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%next = icmp slt i32 %idx.next, %n
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br i1 %next, label %loop, label %exit
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out.of.bounds:
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ret void
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exit:
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ret void
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}
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; CHECK-LABEL: multiple_access_no_preloop
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; CHECK-LABEL: loop.preheader:
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; CHECK: [[smaller_len_cmp:[^ ]+]] = icmp slt i32 %len.a, %len.b
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; CHECK: [[smaller_len:[^ ]+]] = select i1 [[smaller_len_cmp]], i32 %len.a, i32 %len.b
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; CHECK: [[upper_bound_cmp:[^ ]+]] = icmp slt i32 %n, %3
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; CHECK: [[upper_bound:[^ ]+]] = select i1 %5, i32 %n, i32 %3
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; CHECK-LABEL: loop:
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; CHECK: br i1 true, label %in.bounds.a, label %out.of.bounds
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; CHECK-LABEL: in.bounds.a:
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; CHECK: br i1 true, label %in.bounds.b, label %out.of.bounds
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; CHECK-LABEL: in.bounds.b:
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; CHECK: [[main_loop_cond:[^ ]+]] = icmp slt i32 %idx.next, [[upper_bound]]
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; CHECK: br i1 [[main_loop_cond]], label %loop, label %main.exit.selector
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; CHECK-LABEL: in.bounds.b.postloop:
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; CHECK: %next.postloop = icmp slt i32 %idx.next.postloop, %n
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; CHECK: br i1 %next.postloop, label %loop.postloop, label %exit.loopexit
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!0 = !{i32 0, i32 2147483647}
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!1 = !{!"branch_weights", i32 64, i32 4}
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