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path: root/lib/Transforms/Utils/SimplifyCFG.cpp
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2011-02-03SimplifyCFG: Also transform switches that represent a range comparison but ↵Benjamin Kramer
are not sorted into sub+icmp. This transforms another 1000 switches in gcc.c. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124826 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-02SimplifyCFG: Turn switches into sub+icmp+branch if possible.Benjamin Kramer
This makes the job of the later optzn passes easier, allowing the vast amount of icmp transforms to chew on it. We transform 840 switches in gcc.c, leading to a 16k byte shrink of the resulting binary on i386-linux. The testcase from README.txt now compiles into decl %edi cmpl $3, %edi sbbl %eax, %eax andl $1, %eax ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124724 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29Re-apply r124518 with fix. Watch out for invalidated iterator.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124526 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29Revert r124518. It broke Linux self-host.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124522 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-29Re-commit r124462 with fixes. Tail recursion elim will now dup ret into ↵Evan Cheng
unconditional predecessor to enable TCE on demand. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124518 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28Revert r124462. There are a few big regressions that I need to fix first.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124478 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-28- Stop simplifycfg from duplicating "ret" instructions into unconditionalEvan Cheng
branches. PR8575, rdar://5134905, rdar://8911460. - Allow codegen tail duplication to dup small return blocks after register allocation is done. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124462 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-11Factor the actual simplification out of SimplifyIndirectBrOnSelect and into ↵Frits van Bommel
a new helper function so it can be reused in e.g. an upcoming SimplifySwitchOnSelect. No functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123234 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-18simplify this a bit.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122156 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17SimplifyCFG: Ranges can be larger than 64 bits. Fixes Release-selfhost build.Benjamin Kramer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122054 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-17improve switch formation to handle small range Chris Lattner
comparisons formed by comparisons. For example, this: void foo(unsigned x) { if (x == 0 || x == 1 || x == 3 || x == 4 || x == 6) bar(); } compiles into: _foo: ## @foo ## BB#0: ## %entry cmpl $6, %edi ja LBB0_2 ## BB#1: ## %entry movl %edi, %eax movl $91, %ecx btq %rax, %rcx jb LBB0_3 instead of: _foo: ## @foo ## BB#0: ## %entry cmpl $2, %edi jb LBB0_4 ## BB#1: ## %switch.early.test cmpl $6, %edi ja LBB0_3 ## BB#2: ## %switch.early.test movl %edi, %eax movl $88, %ecx btq %rax, %rcx jb LBB0_4 This catches a bunch of cases in GCC, which look like this: %804 = load i32* @which_alternative, align 4, !tbaa !0 %805 = icmp ult i32 %804, 2 %806 = icmp eq i32 %804, 3 %or.cond121 = or i1 %805, %806 %807 = icmp eq i32 %804, 4 %or.cond124 = or i1 %or.cond121, %807 br i1 %or.cond124, label %.thread, label %808 turning this into a range comparison. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122045 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15make qsort predicate more conformant by returning 0 for equal values.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121838 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14 - Insert new instructions before DomBlock's terminator,Chris Lattner
which is simpler than finding a place to insert in BB. - Don't perform the 'if condition hoisting' xform on certain i1 PHIs, as it interferes with switch formation. This re-fixes "example 7", without breaking the world hopefully. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121764 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14fix two significant issues with FoldTwoEntryPHINode:Chris Lattner
first, it can kick in on blocks whose conditions have been folded to a constant, even though one of the edges will be trivially folded. second, it doesn't clean up the "if diamond" that it just eliminated away. This is a problem because other simplifycfg xforms kick in depending on the order of block visitation, causing pointless work. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121762 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14remove the instsimplify logic I added in r121754. It is apparentlyChris Lattner
breaking the selfhost builds, though I can't fathom how. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121761 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14clean up logic, convert std::set to SmallPtrSet, handle the caseChris Lattner
when all 2-entry phis are simplified away. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121760 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14tidy up a bit, move DEBUG down to when we commit to doing the transform so we Chris Lattner
don't print it unless the xform happens. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121758 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14use SimplifyInstruction instead of reimplementing part of it.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121757 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14simplify GetIfCondition by using getSinglePredecessor.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121756 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14use AddPredecessorToBlock in 3 places instead of a manual loop.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121755 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14make FoldTwoEntryPHINode use instsimplify a bit, makeChris Lattner
GetIfCondition faster by avoiding pred_iterator. No really interesting change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121754 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14improve DEBUG's a bit, switch to eraseFromParent() to simplifyChris Lattner
code a bit, switch from constant folding to instsimplify. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121751 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-14reapply my recent change that disables a piece of the switch formationChris Lattner
work, but fixes 400.perlbmk. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121749 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13Fix recent buildbot breakage by pulling SimplifyCFG back to its state as of ↵Owen Anderson
r121694, the most recent state where I'm confident there were no crashes or miscompilations. XFAIL the test added since then for now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121733 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13temporarily disable part of my previous patch, which causes an iterator ↵Chris Lattner
invalidation issue, causing a crash on some versions of perlbmk. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121728 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13add some DEBUG's.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121711 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13Fix sort predicate. qsort(3)'s predicate semantics differ from std::sort's. ↵Benjamin Kramer
Fixes PR 8780. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121705 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13reinstate my patch: the miscompile was caused by an inverted branch in theChris Lattner
'and' case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121695 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13Completely disable the optimization I added in r121680 untilChris Lattner
I can track down a miscompile. This should bring the buildbots back to life git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121693 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13Make simplifycfg reprocess newly formed "br (cond1 | cond2)" conditionsChris Lattner
when simplifying, allowing them to be eagerly turned into switches. This is the last step required to get "Example 7" from this blog post: http://blog.regehr.org/archives/320 On X86, we now generate this machine code, which (to my eye) seems better than the ICC generated code: _crud: ## @crud ## BB#0: ## %entry cmpb $33, %dil jb LBB0_4 ## BB#1: ## %switch.early.test addb $-34, %dil cmpb $58, %dil ja LBB0_3 ## BB#2: ## %switch.early.test movzbl %dil, %eax movabsq $288230376537592865, %rcx ## imm = 0x400000017001421 btq %rax, %rcx jb LBB0_4 LBB0_3: ## %lor.rhs xorl %eax, %eax ret LBB0_4: ## %lor.end movl $1, %eax ret git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121690 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13make this logic a bit simpler.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121689 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13split all the guts of SimplifyCFGOpt::run out into one functionChris Lattner
per terminator kind. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121688 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13fix a bug in r121680 that upset the various buildbots.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121687 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13refactor the speculative execution logic to be factored into the cond branch ↵Chris Lattner
code instead of doing a cfg search for every block simplified. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121686 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13simplify a bunch of code.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121685 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13move HoistThenElseCodeToIf up to a more logical and efficient-to-handle place.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121684 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13move 'MergeBlocksIntoPredecessor' call earlier. UseChris Lattner
getSinglePredecessor to simplify code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121683 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13factor new code out to a SimplifyBranchOnICmpChain helper function.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121681 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13enhance the "change or icmp's into switch" xform to handle one value in an Chris Lattner
'or sequence' that it doesn't understand. This allows us to optimize something insane like this: int crud (unsigned char c, unsigned x) { if(((((((((( (int) c <= 32 || (int) c == 46) || (int) c == 44) || (int) c == 58) || (int) c == 59) || (int) c == 60) || (int) c == 62) || (int) c == 34) || (int) c == 92) || (int) c == 39) != 0) foo(); } into: define i32 @crud(i8 zeroext %c, i32 %x) nounwind ssp noredzone { entry: %cmp = icmp ult i8 %c, 33 br i1 %cmp, label %if.then, label %switch.early.test switch.early.test: ; preds = %entry switch i8 %c, label %if.end [ i8 39, label %if.then i8 44, label %if.then i8 58, label %if.then i8 59, label %if.then i8 60, label %if.then i8 62, label %if.then i8 46, label %if.then i8 92, label %if.then i8 34, label %if.then ] by pulling the < comparison out ahead of the newly formed switch. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121680 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13merge two very similar functions into one that has a bool argument.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121678 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13don't bother handling non-canonical icmp'sChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121676 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13inline a function, making the result much simpler.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121675 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13Fix my previous patch to handle a degenerate case that the llvm-gccChris Lattner
bootstrap buildbot tripped over. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121674 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13convert some methods to be static functionsChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121673 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13zap two more std::sorts.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121672 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13fix a fairly serious oversight with switch formation fromChris Lattner
or'd conditions. Previously we'd compile something like this: int crud (unsigned char c) { return c == 62 || c == 34 || c == 92; } into: switch i8 %c, label %lor.rhs [ i8 62, label %lor.end i8 34, label %lor.end ] lor.rhs: ; preds = %entry %cmp8 = icmp eq i8 %c, 92 br label %lor.end lor.end: ; preds = %entry, %entry, %lor.rhs %0 = phi i1 [ true, %entry ], [ %cmp8, %lor.rhs ], [ true, %entry ] %lor.ext = zext i1 %0 to i32 ret i32 %lor.ext which failed to merge the compare-with-92 into the switch. With this patch we simplify this all the way to: switch i8 %c, label %lor.rhs [ i8 62, label %lor.end i8 34, label %lor.end i8 92, label %lor.end ] lor.rhs: ; preds = %entry br label %lor.end lor.end: ; preds = %entry, %entry, %entry, %lor.rhs %0 = phi i1 [ true, %entry ], [ false, %lor.rhs ], [ true, %entry ], [ true, %entry ] %lor.ext = zext i1 %0 to i32 ret i32 %lor.ext which is much better for codegen's switch lowering stuff. This kicks in 33 times on 176.gcc (for example) cutting 103 instructions off the generated code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121671 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13convert an std::sort to array_pod_sort.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121669 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13move the "br (X == 0 | X == 1), T, F" -> switch optimization to a newChris Lattner
location in simplifycfg. In the old days, SimplifyCFG was never run on the entry block, so we had to scan over all preds of the BB passed into simplifycfg to do this xform, now we can just check blocks ending with a condbranch. This avoids a scan over all preds of every simplified block, which should be a significant compile-time perf win on functions with lots of edges. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121668 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13reduce indentation and generally simplify code, no functionality change.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121667 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-13use getFirstNonPHIOrDbg to simplify this code.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121664 91177308-0d34-0410-b5e6-96231b3b80d8
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