(0.35) Check whether array index variable is an induction variable #15904
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In examining an array index for Idiom Recognition, analyzeOneArrayIndex checks whether the variable operand in a 'var + const' or 'const + var' expression is an induction variable. On the other hand, if the expression is a simple variable, the analysis assumes the variable reference is acceptable. However, it can happen that the variable used as the array index is not an induction variable which can result in an incorrect transformation. Fixed this by adding a check that an arrayindex that is a variable is also an induction variable. Fixes eclipse-openj9#15474 Signed-off-by: Henry Zongaro <zongaro@ca.ibm.com>
pshipton
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Sep 15, 2022
hzongaro
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In examining an array index for Idiom Recognition, analyzeOneArrayIndex checks whether the variable operand in a 'var + const' or 'const + var' expression is an induction variable. On the other hand, if the expression is a simple variable, the analysis assumes the variable reference is acceptable. However, it can happen that the variable used as the array index is not an induction variable which can result in an incorrect transformation.
Fixed this by adding a check that an arrayindex that is a variable is also an induction variable.
Merges pull request #15870 to v0.35.0-release
Fixes #15474
FYI @pshipton