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* [getUnderlyingOjbects] Analyze loop PHIs further to remove false positivesAdam Nemet2015-04-232-0/+138
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Specifically, if a pointer accesses different underlying objects in each iteration, don't look through the phi node defining the pointer. The motivating case is the underlyling-objects-2.ll testcase. Consider the loop nest: int **A; for (i) for (j) A[i][j] = A[i-1][j] * B[j] This loop is transformed by Load-PRE to stash away A[i] for the next iteration of the outer loop: Curr = A[0]; // Prev_0 for (i: 1..N) { Prev = Curr; // Prev = PHI (Prev_0, Curr) Curr = A[i]; for (j: 0..N) Curr[j] = Prev[j] * B[j] } Since A[i] and A[i-1] are likely to be independent pointers, getUnderlyingObjects should not assume that Curr and Prev share the same underlying object in the inner loop. If it did we would try to dependence-analyze Curr and Prev and the analysis of the corresponding SCEVs would fail with non-constant distance. To fix this, the getUnderlyingObjects API is extended with an optional LoopInfo parameter. This is effectively what controls whether we want the above behavior or the original. Currently, I only changed to use this approach for LoopAccessAnalysis. The other testcase is to guard the opposite case where we do want to look through the loop PHI. If we step through an array by incrementing a pointer, the underlying object is the incoming value of the phi as the loop is entered. Fixes rdar://problem/19566729 llvm-svn: 235634
* [LoopAccesses] Properly print whether memchecks are neededAdam Nemet2015-04-141-0/+43
| | | | | | | | | | | Fix oversight in -analyze output. PtrRtCheck contains the pointers that need to be checked against each other and not whether memchecks are necessary. For instance in the testcase PtrRtCheck has four elements but all no-alias so no checking is necessary. llvm-svn: 234833
* [LoopAccesses] Allow analysis to complete in the presence of uniform storesAdam Nemet2015-04-083-0/+160
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | (Re-apply r234361 with a fix and a testcase for PR23157) Both run-time pointer checking and the dependence analysis are capable of dealing with uniform addresses. I.e. it's really just an orthogonal property of the loop that the analysis computes. Run-time pointer checking will only try to reason about SCEVAddRec pointers or else gives up. If the uniform pointer turns out the be a SCEVAddRec in an outer loop, the run-time checks generated will be correct (start and end bounds would be equal). In case of the dependence analysis, we work again with SCEVs. When compared against a loop-dependent address of the same underlying object, the difference of the two SCEVs won't be constant. This will result in returning an Unknown dependence for the pair. When compared against another uniform access, the difference would be constant and we should return the right type of dependence (forward/backward/etc). The changes also adds support to query this property of the loop and modify the vectorizer to use this. Patch by Ashutosh Nema! llvm-svn: 234424
* Revert "[LoopAccesses] Allow analysis to complete in the presence of uniform ↵Adam Nemet2015-04-082-107/+0
| | | | | | | | | | stores" This reverts commit r234361. It caused PR23157. llvm-svn: 234387
* [LoopAccesses] Allow analysis to complete in the presence of uniform storesAdam Nemet2015-04-072-0/+107
| | | | | | | | | | | | | | | | | | | | | | | | | | | Both run-time pointer checking and the dependence analysis are capable of dealing with uniform addresses. I.e. it's really just an orthogonal property of the loop that the analysis computes. Run-time pointer checking will only try to reason about SCEVAddRec pointers or else gives up. If the uniform pointer turns out the be a SCEVAddRec in an outer loop, the run-time checks generated will be correct (start and end bounds would be equal). In case of the dependence analysis, we work again with SCEVs. When compared against a loop-dependent address of the same underlying object, the difference of the two SCEVs won't be constant. This will result in returning an Unknown dependence for the pair. When compared against another uniform access, the difference would be constant and we should return the right type of dependence (forward/backward/etc). The changes also adds support to query this property of the loop and modify the vectorizer to use this. Patch by Ashutosh Nema! llvm-svn: 234361
* [LoopAccesses] Remove unused global variables in testsAdam Nemet2015-04-022-2/+0
| | | | llvm-svn: 233887
* [LoopAccesses 3/3] Print the dependences with -analyzeAdam Nemet2015-03-102-66/+4
| | | | | | | | | | The dependences are now expose through the new getInterestingDependences API so we can use that with -analyze too and fix the FIXME. This lets us remove the test that relied on -debug to check the dependences. llvm-svn: 231807
* [opaque pointer type] Add textual IR support for explicit type parameter to ↵David Blaikie2015-02-273-17/+17
| | | | | | | | | | | | | | | | | | | | | | | | load instruction Essentially the same as the GEP change in r230786. A similar migration script can be used to update test cases, though a few more test case improvements/changes were required this time around: (r229269-r229278) import fileinput import sys import re pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)") for line in sys.stdin: sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line)) Reviewers: rafael, dexonsmith, grosser Differential Revision: http://reviews.llvm.org/D7649 llvm-svn: 230794
* [opaque pointer type] Add textual IR support for explicit type parameter to ↵David Blaikie2015-02-273-19/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | getelementptr instruction One of several parallel first steps to remove the target type of pointers, replacing them with a single opaque pointer type. This adds an explicit type parameter to the gep instruction so that when the first parameter becomes an opaque pointer type, the type to gep through is still available to the instructions. * This doesn't modify gep operators, only instructions (operators will be handled separately) * Textual IR changes only. Bitcode (including upgrade) and changing the in-memory representation will be in separate changes. * geps of vectors are transformed as: getelementptr <4 x float*> %x, ... ->getelementptr float, <4 x float*> %x, ... Then, once the opaque pointer type is introduced, this will ultimately look like: getelementptr float, <4 x ptr> %x with the unambiguous interpretation that it is a vector of pointers to float. * address spaces remain on the pointer, not the type: getelementptr float addrspace(1)* %x ->getelementptr float, float addrspace(1)* %x Then, eventually: getelementptr float, ptr addrspace(1) %x Importantly, the massive amount of test case churn has been automated by same crappy python code. I had to manually update a few test cases that wouldn't fit the script's model (r228970,r229196,r229197,r229198). The python script just massages stdin and writes the result to stdout, I then wrapped that in a shell script to handle replacing files, then using the usual find+xargs to migrate all the files. update.py: import fileinput import sys import re ibrep = re.compile(r"(^.*?[^%\w]getelementptr inbounds )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))") normrep = re.compile( r"(^.*?[^%\w]getelementptr )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))") def conv(match, line): if not match: return line line = match.groups()[0] if len(match.groups()[5]) == 0: line += match.groups()[2] line += match.groups()[3] line += ", " line += match.groups()[1] line += "\n" return line for line in sys.stdin: if line.find("getelementptr ") == line.find("getelementptr inbounds"): if line.find("getelementptr inbounds") != line.find("getelementptr inbounds ("): line = conv(re.match(ibrep, line), line) elif line.find("getelementptr ") != line.find("getelementptr ("): line = conv(re.match(normrep, line), line) sys.stdout.write(line) apply.sh: for name in "$@" do python3 `dirname "$0"`/update.py < "$name" > "$name.tmp" && mv "$name.tmp" "$name" rm -f "$name.tmp" done The actual commands: From llvm/src: find test/ -name *.ll | xargs ./apply.sh From llvm/src/tools/clang: find test/ -name *.mm -o -name *.m -o -name *.cpp -o -name *.c | xargs -I '{}' ../../apply.sh "{}" From llvm/src/tools/polly: find test/ -name *.ll | xargs ./apply.sh After that, check-all (with llvm, clang, clang-tools-extra, lld, compiler-rt, and polly all checked out). The extra 'rm' in the apply.sh script is due to a few files in clang's test suite using interesting unicode stuff that my python script was throwing exceptions on. None of those files needed to be migrated, so it seemed sufficient to ignore those cases. Reviewers: rafael, dexonsmith, grosser Differential Revision: http://reviews.llvm.org/D7636 llvm-svn: 230786
* [LV/LoopAccesses] Backward dependences are not safe just because theAdam Nemet2015-02-261-0/+50
| | | | | | | | | | | accesses are via different types Noticed this while generalizing the code for loop distribution. I confirmed with Arnold that this was indeed a bug and managed to create a testcase. llvm-svn: 230647
* [LoopAccesses] Add -analyze supportAdam Nemet2015-02-192-0/+121
| | | | | | | | | | | | | | | | The LoopInfo in combination with depth_first is used to enumerate the loops. Right now -analyze is not yet complete. It only prints the result of the analysis, the report and the run-time checks. Printing the unsafe depedences will require a bit more reshuffling which I'd like to do in a follow-on to this patchset. Unsafe dependences are currently checked via -debug-only=loop-accesses in the new test. This is part of the patchset that converts LoopAccessAnalysis into an actual analysis pass. llvm-svn: 229898
* Revert r229622: "[LoopAccesses] Make VectorizerParams global" and others. ↵NAKAMURA Takumi2015-02-182-121/+0
| | | | | | | | | | | | | | | | | | r229622 brought cyclic dependencies between Analysis and Vector. r229622: "[LoopAccesses] Make VectorizerParams global" r229623: "[LoopAccesses] Stash the report from the analysis rather than emitting it" r229624: "[LoopAccesses] Cache the result of canVectorizeMemory" r229626: "[LoopAccesses] Create the analysis pass" r229628: "[LoopAccesses] Change debug messages from LV to LAA" r229630: "[LoopAccesses] Add canAnalyzeLoop" r229631: "[LoopAccesses] Add missing const to APIs in VectorizationReport" r229632: "[LoopAccesses] Split out LoopAccessReport from VectorizerReport" r229633: "[LoopAccesses] Add -analyze support" r229634: "[LoopAccesses] Change LAA:getInfo to return a constant reference" r229638: "Analysis: fix buildbots" llvm-svn: 229650
* [LoopAccesses] Add -analyze supportAdam Nemet2015-02-182-0/+121
The LoopInfo in combination with depth_first is used to enumerate the loops. Right now -analyze is not yet complete. It only prints the result of the analysis, the report and the run-time checks. Printing the unsafe depedences will require a bit more reshuffling which I'd like to do in a follow-on to this patchset. Unsafe dependences are currently checked via -debug-only=loop-accesses in the new test. This is part of the patchset that converts LoopAccessAnalysis into an actual analysis pass. llvm-svn: 229633
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