llvm/test/Transforms/ScalarRepl/phinodepromote.ll
Chris Lattner 1fb6e41822 Instcombine now helps out with these
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16405 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-19 18:45:45 +00:00

38 lines
1.2 KiB
LLVM

; RUN: llvm-as < %s | opt -instcombine -mem2reg | llvm-dis | not grep alloca
;
; This tests to see if mem2reg can promote alloca instructions whose addresses
; are used by PHI nodes that are immediately loaded. The LLVM C++ front-end
; often generates code that looks like this (when it codegen's ?: exprs as
; lvalues), so handling this simple extension is quite useful.
;
; This testcase is what the following program looks like when it reaches
; instcombine:
;
; template<typename T>
; const T& max(const T& a1, const T& a2) { return a1 < a2 ? a1 : a2; }
; int main() { return max(0, 1); }
;
; This test checks to make sure the combination of instcombine and mem2reg
; perform the transformation.
int %main() {
entry:
%mem_tmp.0 = alloca int
%mem_tmp.1 = alloca int
store int 0, int* %mem_tmp.0
store int 1, int* %mem_tmp.1
%tmp.1.i = load int* %mem_tmp.1
%tmp.3.i = load int* %mem_tmp.0
%tmp.4.i = setle int %tmp.1.i, %tmp.3.i
br bool %tmp.4.i, label %cond_true.i, label %cond_continue.i
cond_true.i:
br label %cond_continue.i
cond_continue.i:
%mem_tmp.i.0 = phi int* [ %mem_tmp.1, %cond_true.i ], [ %mem_tmp.0, %entry ]
%tmp.3 = load int* %mem_tmp.i.0
ret int %tmp.3
}