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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [X86] error in backend: "Cannot select: t203: v8i32 = BUILD_VECTOR MOV32r0:i32,i32" after r327898"
href="https://bugs.llvm.org/show_bug.cgi?id=36865">36865</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[X86] error in backend: "Cannot select: t203: v8i32 = BUILD_VECTOR MOV32r0:i32,i32" after r327898
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>ilia.taraban@intel.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>This test fails at compilation with "Cannot select: t203: v8i32 = BUILD_VECTOR
MOV32r0:i32,i32" in "X86 DAG->DAG Instruction Selection" on haswell:
================= nice.c ==============
unsigned int l, k;
int main () {
unsigned int i, j, m;
unsigned int a [40] = {0};
unsigned int * pl = & l;
scanf("%u", & m);
for (i = 1; i < 20; ++i)
k += a[i];
for (j = 38; j > 1; --j) {
* pl += l;
a[j] = m - (m * m);
}
return 0;
}
=======================================
<span class="quote">>>> clang -v</span >
clang version 7.0.0 (trunk 328186)
Target: x86_64-unknown-linux-gnu
Thread model: posix
...
<span class="quote">>>> clang nice.c -O2 -march=haswell</span >
fatal error: error in backend: Cannot select: t203: v8i32 = BUILD_VECTOR
MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32,
MOV32r0:i32,i32, MOV32r0:i32,i32,
MOV32r0:i32,i32, MOV32r0:i32,i32
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
t202: i32,i32 = MOV32r0
In function: main
clang-7.0: error: clang frontend command failed with exit code 70 (use -v to
see invocation)
clang version 7.0.0 (trunk 328186)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: .../last_debug/bin
clang-7.0: note: diagnostic msg: PLEASE submit a bug report to
<a href="https://bugs.llvm.org/">https://bugs.llvm.org/</a> and include the crash backtrace, preprocessed source,
and associated run script.
clang-7.0: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-7.0: note: diagnostic msg: /tmp/nice-e7c2be.c
clang-7.0: note: diagnostic msg: /tmp/nice-e7c2be.sh
clang-7.0: note: diagnostic msg:
********************
<span class="quote">>>> clang nice.c -O2 -march=haswell -mllvm -opt-bisect-limit=-1</span >
BISECT: running pass (102) CodeGen Prepare on function (main)
BISECT: running pass (103) X86 DAG->DAG Instruction Selection on function
(main)
fatal error: error in backend: Cannot select: t203: v8i32 = BUILD_VECTOR
MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32,
MOV32r0:i32,i32, MOV32r0:i32,i32,
MOV32r0:i32,i32, MOV32r0:i32,i32
t202: i32,i32 = MOV32r0
...
Here is "small" reproducer for llc:
================= fine.ll =============
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nounwind uwtable
define void @main() #0 {
entry:
%k = alloca i32, align 4
%m = alloca i32, align 4
%a = alloca [100 x i32], align 16
%0 = bitcast [100 x i32]* %a to i8*
call void @llvm.memset.p0i8.i64(i8* nonnull align 16 %0, i8 0, i64 400, i1
false)
%arrayidx = getelementptr inbounds [100 x i32], [100 x i32]* %a, i64 0, i64
34
%add = load i32, i32* %k
%1 = load i32, i32* null
%2 = load i32, i32* undef
%3 = load i32, i32* undef
%4 = load i32, i32* %arrayidx
%5 = load i32, i32* undef
%6 = load i32, i32* undef
%7 = load i32, i32* undef
%8 = load i32, i32* undef
%9 = load i32, i32* undef
%10 = load i32, i32* undef
%11 = load i32, i32* undef
%12 = load i32, i32* undef
%13 = load i32, i32* undef
%14 = load i32, i32* undef
%15 = load i32, i32* undef
%16 = load i32, i32* undef
%add.1 = add i32 %add, %1
%add.2 = add i32 %add.1, %2
%add.3 = add i32 %add.2, %3
%add.4 = add i32 %add.3, %4
store i32 %add.4, i32* %k
%17 = load i32, i32* %m
%mul = mul i32 %17, %17
%sub = sub i32 %17, %mul
store i32 %sub, i32* undef
unreachable
}
; Function Attrs: argmemonly nounwind
declare void @llvm.memset.p0i8.i64(i8* nocapture writeonly, i8, i64, i1) #1
attributes #0 = { nounwind uwtable "target-features"="+avx" }
attributes #1 = { argmemonly nounwind }
=======================================
<span class="quote">>>> llc fine.ll</span >
LLVM ERROR: Cannot select: t75: v8i32 = BUILD_VECTOR MOV32r0:i32,i32,
MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32,
MOV32r0:i32,i32, MOV32r0:i32,i32, MOV32r0:i32,i32
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
t74: i32,i32 = MOV32r0
In function: main
This error appears after r327898:
------------------------------------------------------------------------
r327898 | niravd | 2018-03-19 21:19:46 +0100 (Mon, 19 Mar 2018) | 4 lines
[DAG, X86] Revert r327197 "Revert r327170, r327171, r327172"
Reland ISel cycle checking improvements after simplifying node id
invariant traversal and correcting typo.
------------------------------------------------------------------------</pre>
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