llvm-6502/test/CodeGen/AArch64/machine_cse.ll
Jiangning Liu 0679d2d0a4 In Machine CSE pass, the source register of a COPY machine instruction can
be propagated to all its users, and this propagation could increase the 
probability of finding common subexpressions. If the COPY has only one user,
the COPY itself can be removed.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215344 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-11 05:17:19 +00:00

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1.0 KiB
LLVM

; RUN: llc < %s -mtriple=aarch64-linux-gnuabi -O2 | FileCheck %s
; marked as external to prevent possible optimizations
@a = external global i32
@b = external global i32
@c = external global i32
@d = external global i32
@e = external global i32
define void @combine-sign-comparisons-by-cse(i32 *%arg) {
; CHECK: cmp
; CHECK: b.ge
; CHECK-NOT: cmp
; CHECK: b.le
entry:
%a = load i32* @a, align 4
%b = load i32* @b, align 4
%c = load i32* @c, align 4
%d = load i32* @d, align 4
%e = load i32* @e, align 4
%cmp = icmp slt i32 %a, %e
br i1 %cmp, label %land.lhs.true, label %lor.lhs.false
land.lhs.true:
%cmp1 = icmp eq i32 %b, %c
br i1 %cmp1, label %return, label %if.end
lor.lhs.false:
%cmp2 = icmp sgt i32 %a, %e
br i1 %cmp2, label %land.lhs.true3, label %if.end
land.lhs.true3:
%cmp4 = icmp eq i32 %b, %d
br i1 %cmp4, label %return, label %if.end
if.end:
br label %return
return:
%retval.0 = phi i32 [ 0, %if.end ], [ 1, %land.lhs.true3 ], [ 1, %land.lhs.true ]
store i32 %a, i32 *%arg
ret void
}