mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-27 13:30:05 +00:00
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
|
|
|
|
define void @multiple_access_no_preloop(
|
|
i32* %arr_a, i32* %a_len_ptr, i32* %arr_b, i32* %b_len_ptr, i32 %n) {
|
|
|
|
entry:
|
|
%len.a = load i32* %a_len_ptr, !range !0
|
|
%len.b = load i32* %b_len_ptr, !range !0
|
|
%first.itr.check = icmp sgt i32 %n, 0
|
|
br i1 %first.itr.check, label %loop, label %exit
|
|
|
|
loop:
|
|
%idx = phi i32 [ 0, %entry ] , [ %idx.next, %in.bounds.b ]
|
|
%idx.next = add i32 %idx, 1
|
|
%abc.a = icmp slt i32 %idx, %len.a
|
|
br i1 %abc.a, label %in.bounds.a, label %out.of.bounds, !prof !1
|
|
|
|
in.bounds.a:
|
|
%addr.a = getelementptr i32* %arr_a, i32 %idx
|
|
store i32 0, i32* %addr.a
|
|
%abc.b = icmp slt i32 %idx, %len.b
|
|
br i1 %abc.b, label %in.bounds.b, label %out.of.bounds, !prof !1
|
|
|
|
in.bounds.b:
|
|
%addr.b = getelementptr i32* %arr_b, i32 %idx
|
|
store i32 -1, i32* %addr.b
|
|
%next = icmp slt i32 %idx.next, %n
|
|
br i1 %next, label %loop, label %exit
|
|
|
|
out.of.bounds:
|
|
ret void
|
|
|
|
exit:
|
|
ret void
|
|
}
|
|
|
|
; CHECK-LABEL: multiple_access_no_preloop
|
|
|
|
; CHECK-LABEL: loop.preheader:
|
|
; CHECK: [[smaller_len_cmp:[^ ]+]] = icmp slt i32 %len.a, %len.b
|
|
; CHECK: [[smaller_len:[^ ]+]] = select i1 [[smaller_len_cmp]], i32 %len.a, i32 %len.b
|
|
; CHECK: [[upper_bound_cmp:[^ ]+]] = icmp slt i32 %n, %3
|
|
; CHECK: [[upper_bound:[^ ]+]] = select i1 %5, i32 %n, i32 %3
|
|
|
|
; CHECK-LABEL: loop:
|
|
; CHECK: br i1 true, label %in.bounds.a, label %out.of.bounds
|
|
|
|
; CHECK-LABEL: in.bounds.a:
|
|
; CHECK: br i1 true, label %in.bounds.b, label %out.of.bounds
|
|
|
|
; CHECK-LABEL: in.bounds.b:
|
|
; CHECK: [[main_loop_cond:[^ ]+]] = icmp slt i32 %idx.next, [[upper_bound]]
|
|
; CHECK: br i1 [[main_loop_cond]], label %loop, label %main.exit.selector
|
|
|
|
; CHECK-LABEL: in.bounds.b.postloop:
|
|
; CHECK: %next.postloop = icmp slt i32 %idx.next.postloop, %n
|
|
; CHECK: br i1 %next.postloop, label %loop.postloop, label %exit.loopexit
|
|
|
|
!0 = !{i32 0, i32 2147483647}
|
|
!1 = !{!"branch_weights", i32 64, i32 4}
|