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Reverting r275115 which caused PR28634. 

When empty (forwarding) basic blocks that are referenced by user labels
are removed, incorrect code may be generated.

llvm-svn: 276361
This commit is contained in:
Wolfgang Pieb 2016-07-21 23:28:18 +00:00
parent 18fa9d3ca1
commit 24e03341af
2 changed files with 1 additions and 49 deletions
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14
clang/lib/CodeGen/CGStmt.cpp
View File

@ -623,14 +623,7 @@ void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
RunCleanupsScope ThenScope(*this);
EmitStmt(S.getThen());
}
{
auto CurBlock = Builder.GetInsertBlock();
EmitBranch(ContBlock);
// Eliminate any empty blocks that may have been created by nested
// control flow statements in the 'then' clause.
if (CurBlock)
SimplifyForwardingBlocks(CurBlock);
}
EmitBranch(ContBlock);
// Emit the 'else' code if present.
if (const Stmt *Else = S.getElse()) {
@ -646,12 +639,7 @@ void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
{
// There is no need to emit line number for an unconditional branch.
auto NL = ApplyDebugLocation::CreateEmpty(*this);
auto CurBlock = Builder.GetInsertBlock();
EmitBranch(ContBlock);
// Eliminate any empty blocks that may have been created by nested
// control flow statements emitted in the 'else' clause.
if (CurBlock)
SimplifyForwardingBlocks(CurBlock);
}
}

36
clang/test/CodeGen/forwarding-blocks-if.c
View File

@ -1,36 +0,0 @@
// RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
// Check that no empty blocks are generated for nested ifs.
extern void func();
int f0(int val) {
if (val == 0) {
func();
} else if (val == 1) {
func();
}
return 0;
}
// CHECK-LABEL: define {{.*}}i32 @f0
// CHECK: call void {{.*}} @func
// CHECK: call void {{.*}} @func
// CHECK: br label %[[RETBLOCK1:[^ ]*]]
// CHECK: [[RETBLOCK1]]:
// CHECK-NOT: br label
// CHECK: ret i32
int f1(int val, int g) {
if (val == 0)
if (g == 1) {
func();
}
return 0;
}
// CHECK-LABEL: define {{.*}}i32 @f1
// CHECK: call void {{.*}} @func
// CHECK: br label %[[RETBLOCK2:[^ ]*]]
// CHECK: [[RETBLOCK2]]:
// CHECK-NOT: br label
// CHECK: ret i32