35 lines
1.4 KiB
LLVM
35 lines
1.4 KiB
LLVM
; RUN: opt < %s -simplifycfg -instcombine -mem2reg -S | not grep alloca
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;
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; This tests to see if mem2reg can promote alloca instructions whose addresses
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; are used by PHI nodes that are immediately loaded. The LLVM C++ front-end
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; often generates code that looks like this (when it codegen's ?: exprs as
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; lvalues), so handling this simple extension is quite useful.
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;
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; This testcase is what the following program looks like when it reaches
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; instcombine:
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;
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; template<typename T>
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; const T& max(const T& a1, const T& a2) { return a1 < a2 ? a1 : a2; }
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; int main() { return max(0, 1); }
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;
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; This test checks to make sure the combination of instcombine and mem2reg
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; perform the transformation.
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define i32 @main() {
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entry:
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%mem_tmp.0 = alloca i32 ; <i32*> [#uses=3]
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%mem_tmp.1 = alloca i32 ; <i32*> [#uses=3]
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store i32 0, i32* %mem_tmp.0
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store i32 1, i32* %mem_tmp.1
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%tmp.1.i = load i32, i32* %mem_tmp.1 ; <i32> [#uses=1]
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%tmp.3.i = load i32, i32* %mem_tmp.0 ; <i32> [#uses=1]
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%tmp.4.i = icmp sle i32 %tmp.1.i, %tmp.3.i ; <i1> [#uses=1]
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br i1 %tmp.4.i, label %cond_true.i, label %cond_continue.i
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cond_true.i: ; preds = %entry
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br label %cond_continue.i
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cond_continue.i: ; preds = %cond_true.i, %entry
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%mem_tmp.i.0 = phi i32* [ %mem_tmp.1, %cond_true.i ], [ %mem_tmp.0, %entry ] ; <i32*> [#uses=1]
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%tmp.3 = load i32, i32* %mem_tmp.i.0 ; <i32> [#uses=1]
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ret i32 %tmp.3
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}
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