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path: root/lib/Transforms/Scalar/CodeGenPrepare.cpp
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2012-09-04Generic Bypass Slow DivPreston Gurd
- CodeGenPrepare pass for identifying div/rem ops - Backend specifies the type mapping using addBypassSlowDivType - Enabled only for Intel Atom with O2 32-bit -> 8-bit - Replace IDIV with instructions which test its value and use DIVB if the value is positive and less than 256. - In the case when the quotient and remainder of a divide are used a DIV and a REM instruction will be present in the IR. In the non-Atom case they are both lowered to IDIVs and CSE removes the redundant IDIV instruction, using the quotient and remainder from the first IDIV. However, due to this optimization CSE is not able to eliminate redundant IDIV instructions because they are located in different basic blocks. This is overcome by calculating both the quotient (DIV) and remainder (REM) in each basic block that is inserted by the optimization and reusing the result values when a subsequent DIV or REM instruction uses the same operands. - Test cases check for the presents of the optimization when calculating either the quotient, remainder, or both. Patch by Tyler Nowicki! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163150 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-02Not all targets have efficient ISel code generation for select instructions.Nadav Rotem
For example, the ARM target does not have efficient ISel handling for vector selects with scalar conditions. This patch adds a TLI hook which allows the different targets to report which selects are supported well and which selects should be converted to CF duting codegen prepare. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163093 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-29Make MemoryBuiltins aware of TargetLibraryInfo.Benjamin Kramer
This disables malloc-specific optimization when -fno-builtin (or -ffreestanding) is specified. This has been a problem for a long time but became more severe with the recent memory builtin improvements. Since the memory builtin functions are used everywhere, this required passing TLI in many places. This means that functions that now have an optional TLI argument, like RecursivelyDeleteTriviallyDeadFunctions, won't remove dead mallocs anymore if the TLI argument is missing. I've updated most passes to do the right thing. Fixes PR13694 and probably others. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162841 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-21revise debug output to avoid dangling pointerMichael Liao
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162256 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-15Remove dead flag.Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161990 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-14During the CodeGenPrepare we often lower intrinsics (such as objsize)Nadav Rotem
and allow some optimizations to turn conditional branches into unconditional. This commit adds a simple control-flow optimization which merges two consecutive basic blocks which are connected by a single edge. This allows the codegen to operate on larger basic blocks. rdar://11973998 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161852 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-27Teach CodeGenPrep to look past bitcast when it's duplicating return instructionEvan Cheng
into predecessor blocks to enable tail call optimization. rdar://11958338 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160894 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-25make all Emit*() functions consult the TargetLibraryInfo information before ↵Nuno Lopes
creating a call to a library function. Update all clients to pass the TLI information around. Previous draft reviewed by Eli. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160733 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-24Clean whitespaces.Nadav Rotem
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160668 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-29CodeGenPrepare: Don't crash when TLI is not available.Benjamin Kramer
This happens when codegenprepare is invoked via opt. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159457 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-29Move llvm/Support/IRBuilder.h -> llvm/IRBuilder.hChandler Carruth
This was always part of the VMCore library out of necessity -- it deals entirely in the IR. The .cpp file in fact was already part of the VMCore library. This is just a mechanical move. I've tried to go through and re-apply the coding standard's preferred header sort, but at 40-ish files, I may have gotten some wrong. Please let me know if so. I'll be committing the corresponding updates to Clang and Polly, and Duncan has DragonEgg. Thanks to Bill and Eric for giving the green light for this bit of cleanup. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159421 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-06Switch the select to branch transformation on by default.Benjamin Kramer
The primitive conservative heuristic seems to give a slight overall improvement while not regressing stuff. Make it available to wider testing. If you notice any speed regressions (or significant code size regressions) let me know! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156258 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-05CodeGenPrepare: Add a transform to turn selects into branches in some cases.Benjamin Kramer
This came up when a change in block placement formed a cmov and slowed down a hot loop by 50%: ucomisd (%rdi), %xmm0 cmovbel %edx, %esi cmov is a really bad choice in this context because it doesn't get branch prediction. If we emit it as a branch, an out-of-order CPU can do a better job (if the branch is predicted right) and avoid waiting for the slow load+compare instruction to finish. Of course it won't help if the branch is unpredictable, but those are really rare in practice. This patch uses a dumb conservative heuristic, it turns all cmovs that have one use and a direct memory operand into branches. cmovs usually save some code size, so we disable the transform in -Os mode. In-Order architectures are unlikely to benefit as well, those are included in the "predictableSelectIsExpensive" flag. It would be better to reuse branch probability info here, but BPI doesn't support select instructions currently. It would make sense to use the same heuristics as the if-converter pass, which does the opposite direction of this transform. Test suite shows a small improvement here and there on corei7-level machines, but the actual results depend a lot on the used microarchitecture. The transformation is currently disabled by default and available by passing the -enable-cgp-select2branch flag to the code generator. Thanks to Chandler for the initial test case to him and Evan Cheng for providing me with comments and test-suite numbers that were more stable than mine :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156234 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-24Refactor the interface to recursively simplifying instructions to be tadChandler Carruth
bit simpler by handling a common case explicitly. Also, refactor the implementation to use a worklist based walk of the recursive users, rather than trying to use value handles to detect and recover from RAUWs during the recursive descent. This fixes a very subtle bug in the previous implementation where degenerate control flow structures could cause mutually recursive instructions (PHI nodes) to collapse in just such a way that From became equal to To after some amount of recursion. At that point, we hit the inf-loop that the assert at the top attempted to guard against. This problem is defined away when not using value handles in this manner. There are lots of comments claiming that the WeakVH will protect against just this sort of error, but they're not accurate about the actual implementation of WeakVHs, which do still track RAUWs. I don't have any test case for the bug this fixes because it requires running the recursive simplification on unreachable phi nodes. I've no way to either run this or easily write an input that triggers it. It was found when using instruction simplification inside the inliner when running over the nightly test-suite. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153393 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-13Target override to allow CodeGenPrepare to sink address operands to ↵Pete Cooper
intrinsics in the same way it current does for loads and stores git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152666 91177308-0d34-0410-b5e6-96231b3b80d8
2012-03-04Do trivial CSE of dead BBs during codegen preparation.Bill Wendling
Some BBs can become dead after codegen preparation. If we delete them here, it could help enable tail-call optimizations later on. <rdar://problem/10256573> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152002 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20Extend Attributes to 64 bitsKostya Serebryany
Problem: LLVM needs more function attributes than currently available (32 bits). One such proposed attribute is "address_safety", which shows that a function is being checked for address safety (by AddressSanitizer, SAFECode, etc). Solution: - extend the Attributes from 32 bits to 64-bits - wrap the object into a class so that unsigned is never erroneously used instead - change "unsigned" to "Attributes" throughout the code, including one place in clang. - the class has no "operator uint64 ()", but it has "uint64_t Raw() " to support packing/unpacking. - the class has "safe operator bool()" to support the common idiom: if (Attributes attr = getAttrs()) useAttrs(attr); - The CTOR from uint64_t is marked explicit, so I had to add a few explicit CTOR calls - Add the new attribute "address_safety". Doing it in the same commit to check that attributes beyond first 32 bits actually work. - Some of the functions from the Attribute namespace are worth moving inside the class, but I'd prefer to have it as a separate commit. Tested: "make check" on Linux (32-bit and 64-bit) and Mac (10.6) built/run spec CPU 2006 on Linux with clang -O2. This change will break clang build in lib/CodeGen/CGCall.cpp. The following patch will fix it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148553 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-01Propagate TargetLibraryInfo throughout ConstantFolding.cpp and Chad Rosier
InstructionSimplify.cpp. Other fixups as needed. Part of rdar://10500969 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145559 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-29Fold two identical set lookups into one. No functionality change.Nick Lewycky
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140821 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-27Stop emitting instructions with the name "tmp" they eat up memory and have ↵Benjamin Kramer
to be uniqued, without any benefit. If someone prefers %tmp42 to %42, run instnamer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140634 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-06Use IRBuilder.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139156 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-18Dramatically speedup codegen prepare by a) avoiding use of dominator tree ↵Devang Patel
and b) doing a separate pass over dbg.value instructions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137908 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-16Use the getFirstInsertionPt() method instead of getFirstNonPHI + an 'isa<>'Bill Wendling
check for a LandingPadInst. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137745 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-15In places where it's using "getFirstNonPHI", skip the landingpad instruction ↵Bill Wendling
if necessary. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137679 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-15Skip the insertion iterator past the landingpad instruction if there.Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137626 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18land David Blaikie's patch to de-constify Type, with a few tweaks.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135375 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-29Fix warnings due to 132263; Thanks rdivacky.Nadav Rotem
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132285 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-27Refactor getActionType and getTypeToTransformTo ; place all of the 'decision'Nadav Rotem
code in one place. Re-apply 131534 and fix the multi-step promotion of integers. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132217 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-26Fix warning about || and && without explicit grouping.Chandler Carruth
This looks like it flagged an actual bug. Devang, please review. I added the parentheses that change behavior, but make the behavior more closely match commit log's intent. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132165 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-26Do not insert anything after terminator.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132164 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-26Do not move DBG_VALUE in middle of PHI nodes.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132161 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-26If llvm.dbg.value and the value instruction it refers to are far apart then ↵Devang Patel
iSel may not be able to find corresponding Node for llvm.dbg.value during DAG construction. Make iSel's life easier by removing this distance between llvm.dbg.value and its value instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132151 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-22Add a parameter to ConstantFoldTerminator() that callers can use to ask it ↵Frits van Bommel
to also clean up the condition of any conditional terminator it folds to be unconditional, if that turns the condition into dead code. This just means it calls RecursivelyDeleteTriviallyDeadInstructions() in strategic spots. It defaults to the old behavior. I also changed -simplifycfg, -jump-threading and -codegenprepare to use this to produce slightly better code without any extra cleanup passes (AFAICT this was the only place in -simplifycfg where now-dead conditions of replaced terminators weren't being cleaned up). The only other user of this function is -sccp, but I didn't read that thoroughly enough to figure out whether it might be holding pointers to instructions that could be deleted by this. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131855 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18Revert commit 131534 since it seems to have broken several buildbots.Duncan Sands
Original log entry: Refactor getActionType and getTypeToTransformTo ; place all of the 'decision' code in one place. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131536 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-18Refactor getActionType and getTypeToTransformTo ; place all of the 'decision'Nadav Rotem
code in one place. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131534 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-09Fix a bug where RecursivelyDeleteTriviallyDeadInstructions couldChris Lattner
delete the instruction pointed to by CGP's current instruction iterator, leading to a crash on the testcase. This fixes PR9578. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129200 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24Debug intrinsics must be skipped at the beginning and ends of blocks, lest theyCameron Zwarich
affect the generated code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128217 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24It is enough for the CallInst to have no uses to be made a tail call with a retCameron Zwarich
void; it doesn't need to have a void type. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128212 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24s/UpdateDT/ModifiedDT/gDevang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128211 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24Do early taildup of ret in CodeGenPrepare for potential tail calls that have aCameron Zwarich
void return type. This fixes PR9487. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128197 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24Use an early return instead of a long if block.Cameron Zwarich
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128196 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24When UpdateDT is set, DT is invalid, which could cause problems when trying toCameron Zwarich
use it later. I couldn't make a test that hits this with the current code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128195 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-24Check for TLI so that -codegenprepare can be used from opt.Cameron Zwarich
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128194 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-21Re-apply r127953 with fixes: eliminate empty return block if it has no ↵Evan Cheng
predecessors; update dominator tree if cfg is modified. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127981 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-19Revert r127953, "SimplifyCFG has stopped duplicating returns into predecessorsDaniel Dunbar
to canonicalize IR", it broke a lot of things. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127954 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-19SimplifyCFG has stopped duplicating returns into predecessors to canonicalize IREvan Cheng
to have single return block (at least getting there) for optimizations. This is general goodness but it would prevent some tailcall optimizations. One specific case is code like this: int f1(void); int f2(void); int f3(void); int f4(void); int f5(void); int f6(void); int foo(int x) { switch(x) { case 1: return f1(); case 2: return f2(); case 3: return f3(); case 4: return f4(); case 5: return f5(); case 6: return f6(); } } => LBB0_2: ## %sw.bb callq _f1 popq %rbp ret LBB0_3: ## %sw.bb1 callq _f2 popq %rbp ret LBB0_4: ## %sw.bb3 callq _f3 popq %rbp ret This patch teaches codegenprep to duplicate returns when the return value is a phi and where the phi operands are produced by tail calls followed by an unconditional branch: sw.bb7: ; preds = %entry %call8 = tail call i32 @f5() nounwind br label %return sw.bb9: ; preds = %entry %call10 = tail call i32 @f6() nounwind br label %return return: %retval.0 = phi i32 [ %call10, %sw.bb9 ], [ %call8, %sw.bb7 ], ... [ 0, %entry ] ret i32 %retval.0 This allows codegen to generate better code like this: LBB0_2: ## %sw.bb jmp _f1 ## TAILCALL LBB0_3: ## %sw.bb1 jmp _f2 ## TAILCALL LBB0_4: ## %sw.bb3 jmp _f3 ## TAILCALL rdar://9147433 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127953 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-11Roll r127459 back in:Cameron Zwarich
Optimize trivial branches in CodeGenPrepare, which often get created from the lowering of objectsize intrinsics. Unfortunately, a number of tests were relying on llc not optimizing trivial branches, so I had to add an option to allow them to continue to test what they originally tested. This fixes <rdar://problem/8785296> and <rdar://problem/9112893>. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127498 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-11Revert r127459, "Optimize trivial branches in CodeGenPrepare, which often getDaniel Dunbar
created from the", it broke some GCC test suite tests. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127477 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-11Optimize trivial branches in CodeGenPrepare, which often get created from theCameron Zwarich
lowering of objectsize intrinsics. Unfortunately, a number of tests were relying on llc not optimizing trivial branches, so I had to add an option to allow them to continue to test what they originally tested. This fixes <rdar://problem/8785296> and <rdar://problem/9112893>. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127459 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05Fix PR9398 - 10% of llc compile time is spent in Value::getNumUses. This reducesCameron Zwarich
the percentage of time spent in CodeGenPrepare when llcing 403.gcc from 12.6% to 1.8% of total llc time. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127069 91177308-0d34-0410-b5e6-96231b3b80d8
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