[LSR] Replace casts with an equivalent std::as_const (NFC)

[s-barannikov]

The casts / std::as_const are used here to select const overload of begin()/end() so that the type of the returned iterator matches the type of J, which is const_iterator.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Sergei Barannikov (s-barannikov)

Changes

The casts / std::as_const are used here to select const overload of begin()/end() so that the type of the returned iterator matches the type of J, which is const_iterator.

---

Full diff: https://github.com/llvm/llvm-project/pull/138980.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp (+2-4)

diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 04719fb70552b..464e6e3b2ab97 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3946,10 +3946,8 @@ void LSRInstance::GenerateReassociationsImpl(LSRUse &LU, unsigned LUIdx,
       continue;
 
     // Collect all operands except *J.
-    SmallVector<const SCEV *, 8> InnerAddOps(
-        ((const SmallVector<const SCEV *, 8> &)AddOps).begin(), J);
-    InnerAddOps.append(std::next(J),
-                       ((const SmallVector<const SCEV *, 8> &)AddOps).end());
+    SmallVector<const SCEV *, 8> InnerAddOps(std::as_const(AddOps).begin(), J);
+    InnerAddOps.append(std::next(J), std::as_const(AddOps).end());
 
     // Don't leave just a constant behind in a register if the constant could
     // be folded into an immediate field.

[pfusik]

LGTM. Replacing C-style casts with C++17 as_const, already used in a few places: StaticAnalyzer, MLIR, MLIR elsewhere.

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-aarch64-darwin running on doug-worker-4 while building llvm at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/19657

Here is the relevant piece of the build log for the reference

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang-Unit :: ./AllClangUnitTests/10/48' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests-Clang-Unit-4008-10-48.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=48 GTEST_SHARD_INDEX=10 /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests
--

Note: This is test shard 11 of 48.
[==========] Running 510 tests from 105 test suites.
[----------] Global test environment set-up.
[----------] 1 test from MinimizeSourceToDependencyDirectivesTest
[ RUN      ] MinimizeSourceToDependencyDirectivesTest.DefineInvalidMacroArguments
[       OK ] MinimizeSourceToDependencyDirectivesTest.DefineInvalidMacroArguments (1 ms)
[----------] 1 test from MinimizeSourceToDependencyDirectivesTest (1 ms total)

[----------] 1 test from HeaderMapTest
[ RUN      ] HeaderMapTest.lookupFilenameTruncatedPrefix
[       OK ] HeaderMapTest.lookupFilenameTruncatedPrefix (0 ms)
[----------] 1 test from HeaderMapTest (0 ms total)

[----------] 1 test from ModuleDeclStateTest
[ RUN      ] ModuleDeclStateTest.NamedModuleImplementation
[       OK ] ModuleDeclStateTest.NamedModuleImplementation (5 ms)
[----------] 1 test from ModuleDeclStateTest (5 ms total)

[----------] 1 test from DxcModeTest
[ RUN      ] DxcModeTest.TargetProfileValidation
[       OK ] DxcModeTest.TargetProfileValidation (8 ms)
[----------] 1 test from DxcModeTest (8 ms total)

[----------] 1 test from MultilibTest
[ RUN      ] MultilibTest.SetPushback
[       OK ] MultilibTest.SetPushback (0 ms)
[----------] 1 test from MultilibTest (0 ms total)

[----------] 2 tests from ExprMutationAnalyzerTest
[ RUN      ] ExprMutationAnalyzerTest.CallUnresolved
[       OK ] ExprMutationAnalyzerTest.CallUnresolved (62 ms)
[ RUN      ] ExprMutationAnalyzerTest.RangeForNonArrayByConstRef
input.cc:1:103: warning: expression result unused [-Wunused-value]
    1 | struct V { const int* begin() const; const int* end() const; };void f() { V x; for (const int& e : x) e; }
      |                                                                                                       ^
[       OK ] ExprMutationAnalyzerTest.RangeForNonArrayByConstRef (7 ms)
[----------] 2 tests from ExprMutationAnalyzerTest (69 ms total)

[----------] 1 test from MacroExpansionContextTest
[ RUN      ] MacroExpansionContextTest.StringizingVariadicMacros
[       OK ] MacroExpansionContextTest.StringizingVariadicMacros (0 ms)
[----------] 1 test from MacroExpansionContextTest (0 ms total)

[----------] 1 test from EnvironmentTest
...