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path: root/lib/Transforms/Utils/SimplifyCFG.cpp
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2005-08-02This code was very close, but not quite right. It did not take intoChris Lattner
consideration the case where a reference in an unreachable block could occur. This fixes Transforms/SimplifyCFG/2005-08-01-PHIUpdateFail.ll, something I ran into while bugpoint'ing another pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22584 91177308-0d34-0410-b5e6-96231b3b80d8
2005-06-17Don't crash on: X = phi (X, X).Chris Lattner
This fixes PR584 and Transforms/SimplifyCFG/2005-06-16-PHICrash.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22232 91177308-0d34-0410-b5e6-96231b3b80d8
2005-05-20Fix Transforms/SimplifyCFG/switch-simplify-crash.llChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22158 91177308-0d34-0410-b5e6-96231b3b80d8
2005-05-14Make sure to preserve the calling convention when changing an invoke intoChris Lattner
a call. This fixes Prolangs-C++/deriv2, kimwitu++, and Misc-C++/bigfib on X86 with -enable-x86-fastcc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22023 91177308-0d34-0410-b5e6-96231b3b80d8
2005-04-21Remove trailing whitespaceMisha Brukman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21427 91177308-0d34-0410-b5e6-96231b3b80d8
2005-04-21Teach simplifycfg that setcc is cheap and non-trapping, so that it canChris Lattner
convert this: %tmp.1 = seteq int %i, 0 ; <bool> [#uses=1] br bool %tmp.1, label %shortcirc_done, label %shortcirc_next shortcirc_next: ; preds = %entry %tmp.4 = seteq int %j, 0 ; <bool> [#uses=1] br label %shortcirc_done shortcirc_done: ; preds = %shortcirc_next, %entry %shortcirc_val = phi bool [ %tmp.4, %shortcirc_next ], [ true, %entry ] ; <bool> [#uses=1] to this: %tmp.1 = seteq int %i, 0 ; <bool> [#uses=1] %tmp.4 = seteq int %j, 0 ; <bool> [#uses=1] %shortcirc_val = select bool %tmp.1, bool true, bool %tmp.4 ; <bool> [#uses=1] ... which is later simplified by instcombine into an or. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21388 91177308-0d34-0410-b5e6-96231b3b80d8
2005-04-12Get rid of this for_each loopChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21253 91177308-0d34-0410-b5e6-96231b3b80d8
2005-02-27Fix spelling, patch contributed by Gabor Greif!Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20343 91177308-0d34-0410-b5e6-96231b3b80d8
2005-02-26remove extraneous castChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20334 91177308-0d34-0410-b5e6-96231b3b80d8
2005-02-24Implement Transforms/SimplifyCFG/switch_thread.llChris Lattner
This does a simple form of "jump threading", which eliminates CFG edges that are provably dead. This triggers 90 times in the external tests, and eliminating CFG edges is always always a good thing! :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20300 91177308-0d34-0410-b5e6-96231b3b80d8
2005-01-29switchinst ctor now takes a hint for the number of cases that it will have.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19898 91177308-0d34-0410-b5e6-96231b3b80d8
2005-01-01Implement SimplifyCFG/DeadSetCC.llChris Lattner
SimplifyCFG is one of those passes that we use for final cleanup: it should not rely on other passes to clean up its garbage. This fixes the "why are trivially dead setcc's in the output of gccas" problem. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19212 91177308-0d34-0410-b5e6-96231b3b80d8
2004-12-10Fix Regression/Transforms/SimplifyCFG/2004-12-10-SimplifyCFGCrash.ll,Chris Lattner
and the failure on make_dparser last night. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18766 91177308-0d34-0410-b5e6-96231b3b80d8
2004-11-30Squelch warningChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18381 91177308-0d34-0410-b5e6-96231b3b80d8
2004-11-30Alkis noticed that this variable is dead. Thanks!Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18369 91177308-0d34-0410-b5e6-96231b3b80d8
2004-11-30If we have something like this:Chris Lattner
if (x) { code ... } else { code ... } Turn it into: code if (x) { ... } else { ... } This reduces code size and in some common cases allows us to completely eliminate the conditional. This turns several if/then/else blocks in loops into straightline code in 179.art, turning the loops into single basic blocks (good for modsched even!). Maybe now brg will leave me alone ;-) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18366 91177308-0d34-0410-b5e6-96231b3b80d8
2004-11-01Do not compute the predecessor list for a block unless we need it.Chris Lattner
This speeds up simplifycfg on this program, from 44.87s to 0.29s (with a profiled build): #define CL0(a) case a: goto c; #define CL1(a) CL0(a##0) CL0(a##1) CL0(a##2) CL0(a##3) CL0(a##4) CL0(a##5) \ CL0(a##6) CL0(a##7) CL0(a##8) CL0(a##9) #define CL2(a) CL1(a##0) CL1(a##1) CL1(a##2) CL1(a##3) CL1(a##4) CL1(a##5) \ CL1(a##6) CL1(a##7) CL1(a##8) CL1(a##9) #define CL3(a) CL2(a##0) CL2(a##1) CL2(a##2) CL2(a##3) CL2(a##4) CL2(a##5) \ CL2(a##6) CL2(a##7) CL2(a##8) CL2(a##9) #define CL4(a) CL3(a##0) CL3(a##1) CL3(a##2) CL3(a##3) CL3(a##4) CL3(a##5) \ CL3(a##6) CL3(a##7) CL3(a##8) CL3(a##9) void f(); void a() { int b; c: switch (b) { CL4(1) } } This testcase is contrived to expose N^2 behavior, but this patch should speedup simplifycfg on any programs that use large switch statements. This testcase comes from GCC PR17895. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17389 91177308-0d34-0410-b5e6-96231b3b80d8
2004-10-22Eliminate compilation warning on uninitialized variable.Reid Spencer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17163 91177308-0d34-0410-b5e6-96231b3b80d8
2004-10-18Simplify code by deleting instructions that preceed unreachable instructions.Chris Lattner
Simplify code by simplifying terminators that branch to blocks that start with an unreachable instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17116 91177308-0d34-0410-b5e6-96231b3b80d8
2004-10-14When converting phi nodes into select instructions, we shouldn't promote PHIChris Lattner
nodes unless we KNOW that we are able to promote all of them. This fixes: test/Regression/Transforms/SimplifyCFG/PhiNoEliminate.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16973 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-29Do not insert trivially dead select instructions, which allows us toChris Lattner
potentially fold more in one pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16583 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-15Convert code to compile with vc7.1.Reid Spencer
Patch contributed by Paolo Invernizzi. Thanks Paolo! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16368 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-03Fixes to make LLVM compile with vc7.1.Alkis Evlogimenos
Patch contributed by Paolo Invernizzi! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16152 91177308-0d34-0410-b5e6-96231b3b80d8
2004-09-01Changes For Bug 352Reid Spencer
Move include/Config and include/Support into include/llvm/Config, include/llvm/ADT and include/llvm/Support. From here on out, all LLVM public header files must be under include/llvm/. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16137 91177308-0d34-0410-b5e6-96231b3b80d8
2004-07-21These files don't need to include <iostream> since they include ↵Brian Gaeke
"Support/Debug.h". git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15089 91177308-0d34-0410-b5e6-96231b3b80d8
2004-07-20Implement SimplifyCFG/BrUnwind.llChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15022 91177308-0d34-0410-b5e6-96231b3b80d8
2004-07-18bug 122:Reid Spencer
- Minimize redundant isa<GlobalValue> usage git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14948 91177308-0d34-0410-b5e6-96231b3b80d8
2004-07-15Progress on PR341Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14840 91177308-0d34-0410-b5e6-96231b3b80d8
2004-07-04Add #include <iostream> since Value.h does not #include it any more.Reid Spencer
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14622 91177308-0d34-0410-b5e6-96231b3b80d8
2004-06-21*FINALLY* Fix a really nasty nondeterministic bug that has been haunting usChris Lattner
since May 1st. In this code, the pred iterator was being invalidated sometimes causing the wrong entries to be added to PHI nodes. The fix for this is to defererence and safe the *PI value before we hack on branch instructions, which changes use/def chains, which SOMETIMES invalidates the iterator. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14278 91177308-0d34-0410-b5e6-96231b3b80d8
2004-06-20Add some DEBUG output to the simplifycfg routinesChris Lattner
Fix another non-deterministic behavior, this one should actually speed up the code though as it was doing silly things. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14258 91177308-0d34-0410-b5e6-96231b3b80d8
2004-06-19Do not sort by the address of LLVM ConstantInt* objects. This producesChris Lattner
nondeterministic results that depend on where these objects land in memory. Instead, sort by the value of the constant, which is stable. Before this patch, the -simplifycfg pass run from two different compilers could cause different code to be generated, though it was semantically the same: @@ -12258,8 +12258,8 @@ %s_addr.1 = phi sbyte* [ %s, %entry ], [ %inc.0, %no_exit ] ; <sbyte*> [#uses=5] %tmp.1 = load sbyte* %s_addr.1 ; <sbyte> [#uses=1] switch sbyte %tmp.1, label %no_exit [ - sbyte 0, label %loopexit sbyte 46, label %loopexit + sbyte 0, label %loopexit ] We need to stomp all of this stuff out. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14243 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-02Do not clone arbitrary condition instructions.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13316 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-02Do not infinitely "unroll" single BB loops.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13315 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-02Dont' merge terminators that are needed to select PHI node values.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13312 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-01Implement SimplifyCFG/branch-cond-merge.llChris Lattner
Turning "if (A < B && B < C)" into "if (A < B & B < C)" git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13311 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-01Fix my missing parensChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13307 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-01Implement SimplifyCFG/branch-cond-prop.llChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13306 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-09Fold code like:Chris Lattner
if (C) V1 |= V2; into: Vx = V1 | V2; V1 = select C, V1, Vx when the expression can be evaluated unconditionally and is *cheap* to execute. This limited form of if conversion is quite handy in lots of cases. For example, it turns this testcase into straight-line code: int in0 ; int in1 ; int in2 ; int in3 ; int in4 ; int in5 ; int in6 ; int in7 ; int in8 ; int in9 ; int in10; int in11; int in12; int in13; int in14; int in15; long output; void mux(void) { output = (in0 ? 0x00000001 : 0) | (in1 ? 0x00000002 : 0) | (in2 ? 0x00000004 : 0) | (in3 ? 0x00000008 : 0) | (in4 ? 0x00000010 : 0) | (in5 ? 0x00000020 : 0) | (in6 ? 0x00000040 : 0) | (in7 ? 0x00000080 : 0) | (in8 ? 0x00000100 : 0) | (in9 ? 0x00000200 : 0) | (in10 ? 0x00000400 : 0) | (in11 ? 0x00000800 : 0) | (in12 ? 0x00001000 : 0) | (in13 ? 0x00002000 : 0) | (in14 ? 0x00004000 : 0) | (in15 ? 0x00008000 : 0) ; } git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12798 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-02Fix the obvious bug in my previous checkinChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12618 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-02Implement Transforms/SimplifyCFG/return-merge.llChris Lattner
This actually causes us to turn code like: return C ? A : B; into a select instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12617 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-30Now that all the code generators support the select instruction, and the ↵Chris Lattner
instcombine pass can eliminate many nasty cases of them, start generating them in the optimizers git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12545 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-17Fix compilation of mesa, which I broke earlier todayChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12465 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-16Do not copy gigantic switch instructionsChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12441 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-28Implement switch->br and br->switch folding by ripping out the switch->switchChris Lattner
and br->br code and generalizing it. This allows us to compile code like this: int test(Instruction *I) { if (isa<CastInst>(I)) return foo(7); else if (isa<BranchInst>(I)) return foo(123); else if (isa<UnwindInst>(I)) return foo(1241); else if (isa<SetCondInst>(I)) return foo(1); else if (isa<VAArgInst>(I)) return foo(42); return foo(-1); } into: int %_Z4testPN4llvm11InstructionE("struct.llvm::Instruction"* %I) { entry: %tmp.1.i.i.i.i.i.i.i = getelementptr "struct.llvm::Instruction"* %I, long 0, ubyte 4 ; <uint*> [#uses=1] %tmp.2.i.i.i.i.i.i.i = load uint* %tmp.1.i.i.i.i.i.i.i ; <uint> [#uses=2] %tmp.2.i.i.i.i.i.i = seteq uint %tmp.2.i.i.i.i.i.i.i, 27 ; <bool> [#uses=0] switch uint %tmp.2.i.i.i.i.i.i.i, label %endif.0 [ uint 27, label %then.0 uint 2, label %then.1 uint 5, label %then.2 uint 14, label %then.3 uint 15, label %then.3 uint 16, label %then.3 uint 17, label %then.3 uint 18, label %then.3 uint 19, label %then.3 uint 32, label %then.4 ] ... As well as handling the cases in 176.gcc and many other programs more effectively. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11964 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-26turn things like:Chris Lattner
if (X == 0 || X == 2) ...where the comparisons and branches are in different blocks... into a switch instruction. This comes up a lot in various programs, and works well with the switch/switch merging code I checked earlier. For example, this testcase: int switchtest(int C) { return C == 0 ? f(123) : C == 1 ? f(3123) : C == 4 ? f(312) : C == 5 ? f(1234): f(444); } is converted into this: switch int %C, label %cond_false.3 [ int 0, label %cond_true.0 int 1, label %cond_true.1 int 4, label %cond_true.2 int 5, label %cond_true.3 ] instead of a whole bunch of conditional branches. Admittedly the code is ugly, and incomplete. To be complete, we need to add br -> switch merging and switch -> br merging. For example, this testcase: struct foo { int Q, R, Z; }; #define A (X->Q+X->R * 123) int test(struct foo *X) { return A == 123 ? X1() : A == 12321 ? X2(): (A == 111 || A == 222) ? X3() : A == 875 ? X4() : X5(); } Gets compiled to this: switch int %tmp.7, label %cond_false.2 [ int 123, label %cond_true.0 int 12321, label %cond_true.1 int 111, label %cond_true.2 int 222, label %cond_true.2 ] ... cond_false.2: ; preds = %entry %tmp.52 = seteq int %tmp.7, 875 ; <bool> [#uses=1] br bool %tmp.52, label %cond_true.3, label %cond_false.3 where the branch could be folded into the switch. This kind of thing occurs *ALL OF THE TIME*, especially in programs like 176.gcc, which is a horrible mess of code. It contains stuff like *shudder*: #define SWITCH_TAKES_ARG(CHAR) \ ( (CHAR) == 'D' \ || (CHAR) == 'U' \ || (CHAR) == 'o' \ || (CHAR) == 'e' \ || (CHAR) == 'u' \ || (CHAR) == 'I' \ || (CHAR) == 'm' \ || (CHAR) == 'L' \ || (CHAR) == 'A' \ || (CHAR) == 'h' \ || (CHAR) == 'z') and #define CONST_OK_FOR_LETTER_P(VALUE, C) \ ((C) == 'I' ? SMALL_INTVAL (VALUE) \ : (C) == 'J' ? SMALL_INTVAL (-(VALUE)) \ : (C) == 'K' ? (unsigned)(VALUE) < 32 \ : (C) == 'L' ? ((VALUE) & 0xffff) == 0 \ : (C) == 'M' ? integer_ok_for_set (VALUE) \ : (C) == 'N' ? (VALUE) < 0 \ : (C) == 'O' ? (VALUE) == 0 \ : (C) == 'P' ? (VALUE) >= 0 \ : 0) and #define LEGITIMIZE_ADDRESS(X,OLDX,MODE,WIN) \ { \ if (GET_CODE (X) == PLUS && CONSTANT_ADDRESS_P (XEXP (X, 1))) \ (X) = gen_rtx (PLUS, SImode, XEXP (X, 0), \ copy_to_mode_reg (SImode, XEXP (X, 1))); \ if (GET_CODE (X) == PLUS && CONSTANT_ADDRESS_P (XEXP (X, 0))) \ (X) = gen_rtx (PLUS, SImode, XEXP (X, 1), \ copy_to_mode_reg (SImode, XEXP (X, 0))); \ if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 0)) == MULT) \ (X) = gen_rtx (PLUS, SImode, XEXP (X, 1), \ force_operand (XEXP (X, 0), 0)); \ if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == MULT) \ (X) = gen_rtx (PLUS, SImode, XEXP (X, 0), \ force_operand (XEXP (X, 1), 0)); \ if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 0)) == PLUS) \ (X) = gen_rtx (PLUS, Pmode, force_operand (XEXP (X, 0), NULL_RTX),\ XEXP (X, 1)); \ if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == PLUS) \ (X) = gen_rtx (PLUS, Pmode, XEXP (X, 0), \ force_operand (XEXP (X, 1), NULL_RTX)); \ if (GET_CODE (X) == SYMBOL_REF || GET_CODE (X) == CONST \ || GET_CODE (X) == LABEL_REF) \ (X) = legitimize_address (flag_pic, X, 0, 0); \ if (memory_address_p (MODE, X)) \ goto WIN; } and others. These macros get used multiple times of course. These are such lovely candidates for macros, aren't they? :) This code also nicely handles LLVM constructs that look like this: if (isa<CastInst>(I)) ... else if (isa<BranchInst>(I)) ... else if (isa<SetCondInst>(I)) ... else if (isa<UnwindInst>(I)) ... else if (isa<VAArgInst>(I)) ... where the isa can obviously be a dyn_cast as well. Switch instructions are a good thing. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11870 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24If a block is made dead, make sure to promptly remove it.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11799 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24Implement SimplifyCFG/switch_switch_fold.llChris Lattner
This case occurs many times in various benchmarks, especially when combined with the previous patch. This allows it to get stuff like: if (X == 4 || X == 3) if (X == 5 || X == 8) and switch (X) { case 4: case 5: case 6: if (X == 4 || X == 5) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11797 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24Rearrange code a bitChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11793 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24Implement: test/Regression/Transforms/SimplifyCFG/switch_create.llChris Lattner
This turns code like this: if (X == 4 | X == 7) and if (X != 4 & X != 7) into switch instructions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11792 91177308-0d34-0410-b5e6-96231b3b80d8
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