http://llvm.org/bugs/show_bug.cgi?id=3434
Summary: Wrong x86 code generated
Product: new-bugs
Version: unspecified
Platform: Macintosh
OS/Version: MacOS X
Status: NEW
Severity: normal
Priority: P2
Component: new bugs
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
This is LLVM 2.6svn, rev 63214, generating code for x86.
The code below together with the test program should print 8.
It does print if 8 if optimized (with opt -std-compile-opts),
but with the code straight from the source it prints 1.
Looking at the generated assembly code it looks like the second loop, the one
with the compare instructions, has an empty body.
Maybe there's something wrong with my code, but since it works with
optimization I don't think so.
C code:
-------
#include <stdio.h>
int _fun1(int);
main()
{
printf("%d\n", _fun1(3));
}
LLVM code:
----------
define i32 @_fun1(i32) {
_L1:
br label %_L2
_L2:
%1 = phi i32 [ 0, %_L1 ], [ %6, %_L3 ]
%2 = phi <4 x i32> [ undef, %_L1 ], [ %5, %_L3 ]
%3 = icmp ne i32 %1, 4
br i1 %3, label %_L3, label %_L4
_L3:
%4 = extractelement <4 x i32> < i32 0, i32 1, i32 2, i32 3 >, i32 %1
%5 = insertelement <4 x i32> %2, i32 %0, i32 %1
%6 = add i32 %1, 1
br label %_L2
_L4:
br label %_L5
_L5:
%7 = phi i32 [ 0, %_L4 ], [ %14, %_L6 ]
%8 = phi <4 x i1> [ undef, %_L4 ], [ %13, %_L6 ]
%9 = icmp ne i32 %7, 4
br i1 %9, label %_L6, label %_L7
_L6:
%10 = extractelement <4 x i32> < i32 0, i32 1, i32 2, i32 3 >, i32 %7
%11 = extractelement <4 x i32> %2, i32 %7
%12 = icmp eq i32 %10, %11
%13 = insertelement <4 x i1> %8, i1 %12, i32 %7
%14 = add i32 %7, 1
br label %_L5
_L7:
%15 = bitcast <4 x i1> %8 to i4
%16 = zext i4 %15 to i32
ret i32 %16
}
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