[EXT_EP-11456] When using --opt_level=3, for a loop, compiler may emit assignment to member of a struct in the wrong place Created: 14/Sep/23 Updated: 09/May/24 Resolved: 11/Oct/23 |
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| Status: | Fixed |
| Project: | Embedded Software & Tools |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Bug | Priority: | Medium |
| Reporter: | TI User | Assignee: | TI User |
| Resolution: | Fixed | Votes: | 0 |
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Product: | Code Generation Tools |
| Internal ID: | CODEGEN-11523 |
| Forum URL: | https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1270340/c6000-cgt-loop-optimization-bug-on-8-3-10 |
| Found In Release: | C6000_8.3.0 MSP430_20.2.0.LTS C7000_2.1.0.LTS C2000_22.6.0.B1 PRU_2.3.0 C7000_3.1.0.LTS MSP430_21.6.0.B1 |
| Fix In Release: | MSP430_20.2.8.LTS* C7000_2.1.3.LTS* MSP430_21.6.2.LTS* C7000_3.1.1.LTS C2000_22.6.2.LTS* C6000_8.3.13 C2000_NEXT* PRU_2.3.4* C7000_4.0.0.STS C2000_21.6.2.LTS* |
| Affected Platform/Device: | default |
| Workaround: | To fully avoid this behavior, an optimization level lower than -o2 may be used.
To avoid this behavior in specifically affected code, inserting `__asm(“ NOP”);` between the reads and/or writes of the struct member will prevent reordering the reads and/or writes. For example: my_struct.member = ...; __asm(“ NOP”); ... = my_struct.member; |
| Description |
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This attached code contains these lines ... QualityAndStatus& qualityAndStatus = outResults.qualityAndStatus[idx];
qualityAndStatus.quality = 1.0F;
qualityAndStatus.status = getResultCode(qualityAndStatus.quality, 0);
outResults is a reference to a structure defined from the caller. The value of the first parameter seen in getResultCode is 0.0F, not 1.0F. Build it ... $ cl6x -@options.txt -o3 file.cpp main.cpp -z -o test.out -l lnk.cmd [file.cpp] [main.cpp] <Linking> (Note lnk.cmd is from the \lib directory of the compiler installation.) When executed see ... Result 1 (expect 0): 1 Result 2 (expect 0): 1 Build it again with no optimization (remove -o3) and execute it to see ... Result 1 (expect 0): 0 Result 2 (expect 0): 0 |