llvm-6502/test/Analysis/BranchProbabilityInfo/basic.ll
Manman Ren 1a710fdde1 BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle
the case of multiple edges from one block to another.

A simple example is a switch statement with multiple values to the same
destination. The definition of an edge is modified from a pair of blocks to
a pair of PredBlock and an index into the successors.

Also set the weight correctly when building SelectionDAG from LLVM IR,
especially when converting a Switch.
IntegersSubsetMapping is updated to calculate the weight for each cluster.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162572 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-24 18:14:27 +00:00

118 lines
3.2 KiB
LLVM

; 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}
define i32 @test4(i32 %x) nounwind uwtable readnone ssp {
; CHECK: Printing analysis {{.*}} for function 'test4'
entry:
%conv = sext i32 %x to i64
switch i64 %conv, label %return [
i64 0, label %sw.bb
i64 1, label %sw.bb
i64 2, label %sw.bb
i64 5, label %sw.bb1
], !prof !2
; CHECK: edge entry -> return probability is 7 / 85
; CHECK: edge entry -> sw.bb probability is 14 / 85
; CHECK: edge entry -> sw.bb1 probability is 64 / 85
sw.bb:
br label %return
sw.bb1:
br label %return
return:
%retval.0 = phi i32 [ 5, %sw.bb1 ], [ 1, %sw.bb ], [ 0, %entry ]
ret i32 %retval.0
}
!2 = metadata !{metadata !"branch_weights", i32 7, i32 6, i32 4, i32 4, i32 64}