diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp --- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp +++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp @@ -659,9 +659,6 @@ // checked. if (PHIs.insert(PN).second && !AllUsesOfValueWillTrapIfNull(PN, PHIs)) return false; - } else if (isa(U) && - isa(U->getOperand(1))) { - // Ignore icmp X, null } else { //cerr << "NONTRAPPING USE: " << *U; return false; diff --git a/llvm/test/Transforms/GlobalOpt/null-check-is-use-pr35760.ll b/llvm/test/Transforms/GlobalOpt/null-check-is-use-pr35760.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/GlobalOpt/null-check-is-use-pr35760.ll @@ -0,0 +1,41 @@ +; RUN: opt -S -globalopt -o - < %s | FileCheck %s + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +@_ZL3g_i = internal global i32* null, align 8 +@.str = private unnamed_addr constant [2 x i8] c"0\00", align 1 +@.str.1 = private unnamed_addr constant [2 x i8] c"1\00", align 1 + +define dso_local i32 @main() { + store i32* null, i32** @_ZL3g_i, align 8 + call void @_ZL13PutsSomethingv() + ret i32 0 +} + +; CHECK-LABEL: define {{.*}} @_ZL13PutsSomethingv() +; CHECK: [[gvLoad:%.*]] = load i32*, i32** @_ZL3g_i +; CHECK-NEXT: icmp eq i32* [[gvLoad]], null +define internal void @_ZL13PutsSomethingv() { + %1 = load i32*, i32** @_ZL3g_i, align 8 + %2 = icmp eq i32* %1, null + br i1 %2, label %3, label %7 + +3: ; preds = %0 + %4 = call noalias i8* @malloc(i64 4) #3 + %5 = bitcast i8* %4 to i32* + store i32* %5, i32** @_ZL3g_i, align 8 + %6 = call i32 @puts(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0)) + br label %9 + +7: ; preds = %0 + %8 = call i32 @puts(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0)) + br label %9 + +9: ; preds = %7, %3 + ret void +} + +declare dso_local noalias i8* @malloc(i64) + +declare dso_local i32 @puts(i8* nocapture readonly)