https://llvm.org/bugs/show_bug.cgi?id=27409
Bug ID: 27409
Summary: ScalarEvolution::getConstantEvolutionLoopExitValue
doesn't evualate loops corectly.
Product: new-bugs
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: new bugs
Assignee: unassignedb...@nondot.org
Reporter: willi...@coherentlogix.com
CC: llvm-bugs@lists.llvm.org
Classification: Unclassified
Created attachment 16230
--> https://llvm.org/bugs/attachment.cgi?id=16230&action=edit
Test Case but write up and output files.
When we run the following test case.
#include <stdio.h>
int main() {
int Test[10] = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
int i;
int Sum = 0;
for(i = 0 ; i < 1 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 0 ; i < 2 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 0 ; i < 3 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 3 ; i < 7 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 7 ; i < 10 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 8 ; i < 10 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 9 ; i < 10 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
Sum = 0;
for(i = 0 ; i < 10 ; i++) {
Sum += Test[i] ;
}
printf("Sum = %d\n", Sum);
return 0;
}
We expect the following output:
Sum = 10
Sum = 19
Sum = 27
Sum = 22
Sum = 6
Sum = 3
Sum = 1
Sum = 55
However when we ran this program with clang using -O3 we got the following
output:
Sum = 10
Sum = 10
Sum = 19
Sum = 18
Sum = 6
Sum = 3
Sum = 1
Sum = 55
We have tracked the problem down to the following function:
onstant *
ScalarEvolution::getConstantEvolutionLoopExitValue(PHINode *PN,
const APInt &BEs,
const Loop *L)
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
