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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - Incorrect code generated with tail call" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24353&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=1QvJjvP5MN0vhtWENATwUP9i6SLFxtPaMX_1qT8pQ9Y&s=8da4sLh-uK6SdlFYGNRPrQ6UNhwrVlAGmXsKYyQaSWg&e=">24353</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Incorrect code generated with tail call
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>jbush342@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>clang & llvm @243600
The following code:
#include <stdio.h>
static int function1() {
printf("B\n");
}
void function2() {
function1();
printf("C\n");
}
int main(int argc, const char *argv[]) {
function2();
}
Will go into infinite recursion and crash. When compiled with -O3, function2
generates the following. The function abruptly ends after the first puts call
(printf "B"), and there is no epilogue:
__Z9function2v: ## @_Z9function2v
.cfi_startproc
pushq %rbp
movq %rsp, %rbp
Ltmp2: leaq L_str.2(%rip), %rdi
callq _puts
.cfi_endproc
.globl _main
The LLVM IR has inserted an unreachable after the first inlined call to printf
for some reason:
define void @_Z9function2v() #0 {
entry:
%puts.i = tail call i32 @puts(i8* getelementptr inbounds ([2 x i8], [2 x i8]*
@str.2, i64 0, i64 0)) #1
unreachable
}</pre>
</div>
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