| Issue |
120076
|
| Summary |
[SLPVectorizer] Miscompile at O3
|
| Labels |
miscompilation,
llvm:SLPVectorizer
|
| Assignees |
|
| Reporter |
dtcxzyw
|
Reproducer: https://alive2.llvm.org/ce/z/_88AAB
```
; bin/opt -passes=slp-vectorizer reduced.ll -S
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i8 @func_129() {
entry:
%conv4.i.i = zext i16 0 to i32
%conv7.i.i = sext i16 0 to i32
%cmp8.i.i = icmp slt i32 %conv7.i.i, %conv4.i.i
%conv9.i.i = zext i1 %cmp8.i.i to i32
%or10.i.i = or i32 %conv9.i.i, %conv4.i.i
%cmp11.i.i = icmp eq i32 %or10.i.i, %conv4.i.i
%sub.i.i79.peel.i = sub i16 0, 1
%xor5.i81.peel.i = zext i16 %sub.i.i79.peel.i to i32
%conv7.i84.peel.i = sext i16 0 to i32
%cmp8.i85.peel.i = icmp slt i32 %conv7.i84.peel.i, %xor5.i81.peel.i
%conv9.i86.peel.i = zext i1 %cmp8.i85.peel.i to i32
%or10.i87.peel.i = or i32 %conv9.i86.peel.i, %xor5.i81.peel.i
%cmp11.i88.peel.i = icmp eq i32 %or10.i87.peel.i, %xor5.i81.peel.i
%conv13.i89.peel.i = zext i1 %cmp8.i85.peel.i to i8
ret i8 %conv13.i89.peel.i
}
```
```
define i8 @func_129() {
entry:
%sub.i.i79.peel.i = sub i16 0, 1
%0 = insertelement <2 x i16> <i16 poison, i16 0>, i16 %sub.i.i79.peel.i, i32 0
%1 = icmp slt <2 x i16> zeroinitializer, %0
%2 = zext <2 x i1> %1 to <2 x i16>
%3 = or <2 x i16> %2, %0
%4 = icmp eq <2 x i16> %3, %0
%5 = extractelement <2 x i1> %1, i32 0
%conv13.i89.peel.i = zext i1 %5 to i8
ret i8 %conv13.i89.peel.i
}
```
```
----------------------------------------
define i8 @src() {
entry:
%sub.i.i79.peel.i = sub i16 0, 1
%xor5.i81.peel.i = zext i16 %sub.i.i79.peel.i to i32
%conv7.i84.peel.i = sext i16 0 to i32
%cmp8.i85.peel.i = icmp slt i32 %conv7.i84.peel.i, %xor5.i81.peel.i
%conv13.i89.peel.i = zext i1 %cmp8.i85.peel.i to i8
ret i8 %conv13.i89.peel.i
}
=>
define i8 @tgt() {
entry:
%sub.i.i79.peel.i = sub i16 0, 1
%#0 = insertelement <2 x i16> { poison, 0 }, i16 %sub.i.i79.peel.i, i32 0
%#1 = icmp slt <2 x i16> { 0, 0 }, %#0
%#5 = extractelement <2 x i1> %#1, i32 0
%conv13.i89.peel.i = zext i1 %#5 to i8
ret i8 %conv13.i89.peel.i
}
Transformation doesn't verify!
ERROR: Value mismatch
Example:
Source:
i16 %sub.i.i79.peel.i = #xffff (65535, -1)
i32 %xor5.i81.peel.i = #x0000ffff (65535)
i32 %conv7.i84.peel.i = #x00000000 (0)
i1 %cmp8.i85.peel.i = #x1 (1)
i8 %conv13.i89.peel.i = #x01 (1)
Target:
i16 %sub.i.i79.peel.i = #xffff (65535, -1)
<2 x i16> %#0 = < #xffff (65535, -1), #x0000 (0) >
<2 x i1> %#1 = < #x0 (0), #x0 (0) >
i1 %#5 = #x0 (0)
i8 %conv13.i89.peel.i = #x00 (0)
Source value: #x01 (1)
Target value: #x00 (0)
```
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