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- ; RUN: opt < %s -simplifycfg -instcombine -mem2reg -S | 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.
- define i32 @main() {
- entry:
- %mem_tmp.0 = alloca i32 ; <i32*> [#uses=3]
- %mem_tmp.1 = alloca i32 ; <i32*> [#uses=3]
- store i32 0, i32* %mem_tmp.0
- store i32 1, i32* %mem_tmp.1
- %tmp.1.i = load i32, i32* %mem_tmp.1 ; <i32> [#uses=1]
- %tmp.3.i = load i32, i32* %mem_tmp.0 ; <i32> [#uses=1]
- %tmp.4.i = icmp sle i32 %tmp.1.i, %tmp.3.i ; <i1> [#uses=1]
- br i1 %tmp.4.i, label %cond_true.i, label %cond_continue.i
- cond_true.i: ; preds = %entry
- br label %cond_continue.i
- cond_continue.i: ; preds = %cond_true.i, %entry
- %mem_tmp.i.0 = phi i32* [ %mem_tmp.1, %cond_true.i ], [ %mem_tmp.0, %entry ] ; <i32*> [#uses=1]
- %tmp.3 = load i32, i32* %mem_tmp.i.0 ; <i32> [#uses=1]
- ret i32 %tmp.3
- }
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