diff --git a/include/llvm/Analysis/BranchProbabilityInfo.h b/include/llvm/Analysis/BranchProbabilityInfo.h index a2c12ab9e82..180d230b4c5 100644 --- a/include/llvm/Analysis/BranchProbabilityInfo.h +++ b/include/llvm/Analysis/BranchProbabilityInfo.h @@ -37,6 +37,9 @@ class BranchProbabilityInfo : public FunctionPass { DenseMap Weights; + /// \brief Track the last function we run over for printing. + Function *LastF; + // Get sum of the block successors' weights. uint32_t getSumForBlock(const BasicBlock *BB) const; @@ -48,8 +51,8 @@ public: } void getAnalysisUsage(AnalysisUsage &AU) const; - bool runOnFunction(Function &F); + void print(raw_ostream &OS, const Module *M = 0) const; // Returned value is between 1 and UINT32_MAX. Look at // BranchProbabilityInfo.cpp for details. @@ -74,8 +77,8 @@ public: // Print value between 0 (0% probability) and 1 (100% probability), // however the value is never equal to 0, and can be 1 only iff SRC block // has only one successor. - raw_ostream &printEdgeProbability(raw_ostream &OS, BasicBlock *Src, - BasicBlock *Dst) const; + raw_ostream &printEdgeProbability(raw_ostream &OS, const BasicBlock *Src, + const BasicBlock *Dst) const; }; } diff --git a/lib/Analysis/BranchProbabilityInfo.cpp b/lib/Analysis/BranchProbabilityInfo.cpp index 4f15858aa34..9f175b070d3 100644 --- a/lib/Analysis/BranchProbabilityInfo.cpp +++ b/lib/Analysis/BranchProbabilityInfo.cpp @@ -12,11 +12,13 @@ //===----------------------------------------------------------------------===// #include "llvm/Constants.h" +#include "llvm/Function.h" #include "llvm/Instructions.h" #include "llvm/LLVMContext.h" #include "llvm/Metadata.h" #include "llvm/Analysis/BranchProbabilityInfo.h" #include "llvm/Analysis/LoopInfo.h" +#include "llvm/Support/CFG.h" #include "llvm/Support/Debug.h" using namespace llvm; @@ -453,11 +455,26 @@ void BranchProbabilityInfo::getAnalysisUsage(AnalysisUsage &AU) const { } bool BranchProbabilityInfo::runOnFunction(Function &F) { + LastF = &F; // Store the last function we ran on for printing. LoopInfo &LI = getAnalysis(); BranchProbabilityAnalysis BPA(this, &LI); return BPA.runOnFunction(F); } +void BranchProbabilityInfo::print(raw_ostream &OS, const Module *) const { + OS << "---- Branch Probabilities ----\n"; + // We print the probabilities from the last function the analysis ran over, + // or the function it is currently running over. + assert(LastF && "Cannot print prior to running over a function"); + for (Function::const_iterator BI = LastF->begin(), BE = LastF->end(); + BI != BE; ++BI) { + for (succ_const_iterator SI = succ_begin(BI), SE = succ_end(BI); + SI != SE; ++SI) { + printEdgeProbability(OS << " ", BI, *SI); + } + } +} + uint32_t BranchProbabilityInfo::getSumForBlock(const BasicBlock *BB) const { uint32_t Sum = 0; @@ -537,8 +554,9 @@ getEdgeProbability(const BasicBlock *Src, const BasicBlock *Dst) const { } raw_ostream & -BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS, BasicBlock *Src, - BasicBlock *Dst) const { +BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS, + const BasicBlock *Src, + const BasicBlock *Dst) const { const BranchProbability Prob = getEdgeProbability(Src, Dst); OS << "edge " << Src->getNameStr() << " -> " << Dst->getNameStr() diff --git a/test/Analysis/BranchProbabilityInfo/basic.ll b/test/Analysis/BranchProbabilityInfo/basic.ll new file mode 100644 index 00000000000..74d06a18f7b --- /dev/null +++ b/test/Analysis/BranchProbabilityInfo/basic.ll @@ -0,0 +1,90 @@ +; RUN: opt < %s -analyze -branch-prob | FileCheck %s + +define i32 @test1(i32 %i, i32* %a) { +; CHECK: Printing analysis {{.*}} for function 'test1' +entry: + br label %body +; CHECK: edge entry -> body probability is 16 / 16 = 100% + +body: + %iv = phi i32 [ 0, %entry ], [ %next, %body ] + %base = phi i32 [ 0, %entry ], [ %sum, %body ] + %arrayidx = getelementptr inbounds i32* %a, i32 %iv + %0 = load i32* %arrayidx + %sum = add nsw i32 %0, %base + %next = add i32 %iv, 1 + %exitcond = icmp eq i32 %next, %i + br i1 %exitcond, label %exit, label %body +; CHECK: edge body -> exit probability is 4 / 128 +; CHECK: edge body -> body probability is 124 / 128 + +exit: + ret i32 %sum +} + +define i32 @test2(i32 %i, i32 %a, i32 %b) { +; CHECK: Printing analysis {{.*}} for function 'test2' +entry: + %cond = icmp ult i32 %i, 42 + br i1 %cond, label %then, label %else, !prof !0 +; CHECK: edge entry -> then probability is 64 / 68 +; CHECK: edge entry -> else probability is 4 / 68 + +then: + br label %exit +; CHECK: edge then -> exit probability is 16 / 16 = 100% + +else: + br label %exit +; CHECK: edge else -> exit probability is 16 / 16 = 100% + +exit: + %result = phi i32 [ %a, %then ], [ %b, %else ] + ret i32 %result +} + +!0 = metadata !{metadata !"branch_weights", i32 64, i32 4} + +define i32 @test3(i32 %i, i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) { +; CHECK: Printing analysis {{.*}} for function 'test3' +entry: + switch i32 %i, label %case_a [ i32 1, label %case_b + i32 2, label %case_c + i32 3, label %case_d + i32 4, label %case_e ], !prof !1 +; CHECK: edge entry -> case_a probability is 4 / 80 +; CHECK: edge entry -> case_b probability is 4 / 80 +; CHECK: edge entry -> case_c probability is 64 / 80 +; CHECK: edge entry -> case_d probability is 4 / 80 +; CHECK: edge entry -> case_e probability is 4 / 80 + +case_a: + br label %exit +; CHECK: edge case_a -> exit probability is 16 / 16 = 100% + +case_b: + br label %exit +; CHECK: edge case_b -> exit probability is 16 / 16 = 100% + +case_c: + br label %exit +; CHECK: edge case_c -> exit probability is 16 / 16 = 100% + +case_d: + br label %exit +; CHECK: edge case_d -> exit probability is 16 / 16 = 100% + +case_e: + br label %exit +; CHECK: edge case_e -> exit probability is 16 / 16 = 100% + +exit: + %result = phi i32 [ %a, %case_a ], + [ %b, %case_b ], + [ %c, %case_c ], + [ %d, %case_d ], + [ %e, %case_e ] + ret i32 %result +} + +!1 = metadata !{metadata !"branch_weights", i32 4, i32 4, i32 64, i32 4, i32 4} diff --git a/test/Analysis/BranchProbabilityInfo/dg.exp b/test/Analysis/BranchProbabilityInfo/dg.exp new file mode 100644 index 00000000000..f2005891a59 --- /dev/null +++ b/test/Analysis/BranchProbabilityInfo/dg.exp @@ -0,0 +1,3 @@ +load_lib llvm.exp + +RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.{ll,c,cpp}]]