mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-26 21:32:10 +00:00
075fb5d68f
references. For example, this allows gvn to eliminate the load in
this example:
void foo(int n, int* p, int *q) {
p[0] = 0;
p[1] = 1;
if (n) {
*q = p[0];
}
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118714 91177308-0d34-0410-b5e6-96231b3b80d8
60 lines
1.3 KiB
LLVM
60 lines
1.3 KiB
LLVM
; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
|
|
|
|
target datalayout = "e-p:64:64:64"
|
|
|
|
; GVN should ignore the store to p[1] to see that the load from p[0] is
|
|
; fully redundant.
|
|
|
|
; CHECK: @yes
|
|
; CHECK: if.then:
|
|
; CHECK-NEXT: store i32 0, i32* %q
|
|
; CHECK-NEXT: ret void
|
|
|
|
define void @yes(i1 %c, i32* %p, i32* %q) nounwind {
|
|
entry:
|
|
store i32 0, i32* %p
|
|
%p1 = getelementptr inbounds i32* %p, i64 1
|
|
store i32 1, i32* %p1
|
|
br i1 %c, label %if.else, label %if.then
|
|
|
|
if.then:
|
|
%t = load i32* %p
|
|
store i32 %t, i32* %q
|
|
ret void
|
|
|
|
if.else:
|
|
ret void
|
|
}
|
|
|
|
; GVN should ignore the store to p[1] to see that the first load from p[0] is
|
|
; fully redundant. However, the second load is larger, so it's not a simple
|
|
; redundancy.
|
|
|
|
; CHECK: @watch_out_for_size_change
|
|
; CHECK: if.then:
|
|
; CHECK-NEXT: store i32 0, i32* %q
|
|
; CHECK-NEXT: ret void
|
|
; CHECK: if.else:
|
|
; CHECK: load i64* %pc
|
|
; CHECK: store i64
|
|
|
|
define void @watch_out_for_size_change(i1 %c, i32* %p, i32* %q) nounwind {
|
|
entry:
|
|
store i32 0, i32* %p
|
|
%p1 = getelementptr inbounds i32* %p, i64 1
|
|
store i32 1, i32* %p1
|
|
br i1 %c, label %if.else, label %if.then
|
|
|
|
if.then:
|
|
%t = load i32* %p
|
|
store i32 %t, i32* %q
|
|
ret void
|
|
|
|
if.else:
|
|
%pc = bitcast i32* %p to i64*
|
|
%qc = bitcast i32* %q to i64*
|
|
%t64 = load i64* %pc
|
|
store i64 %t64, i64* %qc
|
|
ret void
|
|
}
|