llvm-project/llvm/test/Analysis/StackSafetyAnalysis
Philip Reames 4a5edea193 [SCEV] Use both known bits and sign bits when computing range of SCEV unknowns
When computing a range for a SCEVUnknown, today we use computeKnownBits for unsigned ranges, and computeNumSignBots for signed ranges. This means we miss opportunities to improve range results.

One common missed pattern is that we have a signed range of a value which CKB can determine is positive, but CNSB doesn't convey that information. The current range includes the negative part, and is thus double the size.

Per the removed comment, the original concern which delayed using both (after some code merging years back) was a compile time concern. CTMark results (provided by Nikita, thanks!) showed a geomean impact of about 0.1%. This doesn't seem large enough to avoid higher quality results.

Differential Revision: https://reviews.llvm.org/D96534
2021-02-19 08:29:12 -08:00
..
Inputs [NFC][StackSafety] noinline in alias tests 2020-08-08 18:21:52 -07:00
ipa-alias.ll [NPM][StackSafetyAnalysis] Pin uses of -analyze to legacy PM 2020-10-19 21:24:03 -07:00
ipa.ll [NPM][StackSafetyAnalysis] Pin uses of -analyze to legacy PM 2020-10-19 21:24:03 -07:00
lifetime.ll [StackSafety] Ignore allocas with partial lifetime markers 2020-08-27 13:54:41 -07:00
local.ll [SCEV] Use both known bits and sign bits when computing range of SCEV unknowns 2021-02-19 08:29:12 -08:00
memintrin.ll [SCEV] Use both known bits and sign bits when computing range of SCEV unknowns 2021-02-19 08:29:12 -08:00