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-rw-r--r--include/llvm/Analysis/BranchProbabilityInfo.h9
-rw-r--r--lib/Analysis/BranchProbabilityInfo.cpp22
-rw-r--r--test/Analysis/BranchProbabilityInfo/basic.ll90
-rw-r--r--test/Analysis/BranchProbabilityInfo/dg.exp3
4 files changed, 119 insertions, 5 deletions
diff --git a/include/llvm/Analysis/BranchProbabilityInfo.h b/include/llvm/Analysis/BranchProbabilityInfo.h
index a2c12ab9e8..180d230b4c 100644
--- a/include/llvm/Analysis/BranchProbabilityInfo.h
+++ b/include/llvm/Analysis/BranchProbabilityInfo.h
@@ -37,6 +37,9 @@ class BranchProbabilityInfo : public FunctionPass {
DenseMap<Edge, uint32_t> 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 4f15858aa3..9f175b070d 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<LoopInfo>();
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 0000000000..74d06a18f7
--- /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 0000000000..f2005891a5
--- /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}]]
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-12 13:32:25 +0000