mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2025-10-31 08:16:47 +00:00
e14fb07357
This adds another heuristic to BPI, similar to the existing heuristic that considers (x == 0) unlikely to be true. As suggested in the PACT'98 paper by Deitrich, Cheng, and Hwu, -1 is often used to indicate an invalid index, and equality comparisons with -1 are also unlikely to succeed. Local experimentation supports this hypothesis: This yields a 1-2% speedup in the test-suite sqlite benchmark on the PPC A2 core, with no significant regressions. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193855 91177308-0d34-0410-b5e6-96231b3b80d8
215 lines
5.6 KiB
LLVM
215 lines
5.6 KiB
LLVM
; RUN: opt < %s -analyze -branch-prob | FileCheck %s
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define i32 @test1(i32 %i, i32* %a) {
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; CHECK: Printing analysis {{.*}} for function 'test1'
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entry:
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br label %body
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; CHECK: edge entry -> body probability is 16 / 16 = 100%
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body:
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%iv = phi i32 [ 0, %entry ], [ %next, %body ]
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%base = phi i32 [ 0, %entry ], [ %sum, %body ]
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%arrayidx = getelementptr inbounds i32* %a, i32 %iv
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%0 = load i32* %arrayidx
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%sum = add nsw i32 %0, %base
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%next = add i32 %iv, 1
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%exitcond = icmp eq i32 %next, %i
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br i1 %exitcond, label %exit, label %body
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; CHECK: edge body -> exit probability is 4 / 128
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; CHECK: edge body -> body probability is 124 / 128
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exit:
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ret i32 %sum
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}
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define i32 @test2(i32 %i, i32 %a, i32 %b) {
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; CHECK: Printing analysis {{.*}} for function 'test2'
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entry:
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%cond = icmp ult i32 %i, 42
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br i1 %cond, label %then, label %else, !prof !0
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; CHECK: edge entry -> then probability is 64 / 68
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; CHECK: edge entry -> else probability is 4 / 68
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then:
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br label %exit
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; CHECK: edge then -> exit probability is 16 / 16 = 100%
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else:
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br label %exit
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; CHECK: edge else -> exit probability is 16 / 16 = 100%
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exit:
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%result = phi i32 [ %a, %then ], [ %b, %else ]
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ret i32 %result
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}
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!0 = metadata !{metadata !"branch_weights", i32 64, i32 4}
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define i32 @test3(i32 %i, i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) {
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; CHECK: Printing analysis {{.*}} for function 'test3'
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entry:
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switch i32 %i, label %case_a [ i32 1, label %case_b
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i32 2, label %case_c
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i32 3, label %case_d
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i32 4, label %case_e ], !prof !1
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; CHECK: edge entry -> case_a probability is 4 / 80
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; CHECK: edge entry -> case_b probability is 4 / 80
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; CHECK: edge entry -> case_c probability is 64 / 80
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; CHECK: edge entry -> case_d probability is 4 / 80
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; CHECK: edge entry -> case_e probability is 4 / 80
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case_a:
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br label %exit
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; CHECK: edge case_a -> exit probability is 16 / 16 = 100%
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case_b:
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br label %exit
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; CHECK: edge case_b -> exit probability is 16 / 16 = 100%
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case_c:
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br label %exit
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; CHECK: edge case_c -> exit probability is 16 / 16 = 100%
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case_d:
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br label %exit
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; CHECK: edge case_d -> exit probability is 16 / 16 = 100%
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case_e:
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br label %exit
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; CHECK: edge case_e -> exit probability is 16 / 16 = 100%
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exit:
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%result = phi i32 [ %a, %case_a ],
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[ %b, %case_b ],
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[ %c, %case_c ],
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[ %d, %case_d ],
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[ %e, %case_e ]
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ret i32 %result
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}
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!1 = metadata !{metadata !"branch_weights", i32 4, i32 4, i32 64, i32 4, i32 4}
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define i32 @test4(i32 %x) nounwind uwtable readnone ssp {
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; CHECK: Printing analysis {{.*}} for function 'test4'
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entry:
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%conv = sext i32 %x to i64
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switch i64 %conv, label %return [
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i64 0, label %sw.bb
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i64 1, label %sw.bb
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i64 2, label %sw.bb
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i64 5, label %sw.bb1
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], !prof !2
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; CHECK: edge entry -> return probability is 7 / 85
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; CHECK: edge entry -> sw.bb probability is 14 / 85
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; CHECK: edge entry -> sw.bb1 probability is 64 / 85
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sw.bb:
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br label %return
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sw.bb1:
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br label %return
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return:
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%retval.0 = phi i32 [ 5, %sw.bb1 ], [ 1, %sw.bb ], [ 0, %entry ]
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ret i32 %retval.0
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}
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!2 = metadata !{metadata !"branch_weights", i32 7, i32 6, i32 4, i32 4, i32 64}
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declare void @coldfunc() cold
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define i32 @test5(i32 %a, i32 %b, i1 %flag) {
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; CHECK: Printing analysis {{.*}} for function 'test5'
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entry:
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br i1 %flag, label %then, label %else
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; CHECK: edge entry -> then probability is 4 / 68
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; CHECK: edge entry -> else probability is 64 / 68
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then:
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call void @coldfunc()
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br label %exit
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; CHECK: edge then -> exit probability is 16 / 16 = 100%
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else:
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br label %exit
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; CHECK: edge else -> exit probability is 16 / 16 = 100%
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exit:
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%result = phi i32 [ %a, %then ], [ %b, %else ]
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ret i32 %result
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}
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declare i32 @regular_function(i32 %i)
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define i32 @test_cold_call_sites(i32* %a) {
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; Test that edges to blocks post-dominated by cold call sites
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; are marked as not expected to be taken.
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; TODO(dnovillo) The calls to regular_function should not be merged, but
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; they are currently being merged. Convert this into a code generation test
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; after that is fixed.
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; CHECK: Printing analysis {{.*}} for function 'test_cold_call_sites'
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; CHECK: edge entry -> then probability is 4 / 68 = 5.88235%
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; CHECK: edge entry -> else probability is 64 / 68 = 94.1176% [HOT edge]
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entry:
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%gep1 = getelementptr i32* %a, i32 1
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%val1 = load i32* %gep1
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%cond1 = icmp ugt i32 %val1, 1
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br i1 %cond1, label %then, label %else
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then:
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; This function is not declared cold, but this call site is.
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%val4 = call i32 @regular_function(i32 %val1) cold
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br label %exit
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else:
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%gep2 = getelementptr i32* %a, i32 2
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%val2 = load i32* %gep2
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%val3 = call i32 @regular_function(i32 %val2)
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br label %exit
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exit:
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%ret = phi i32 [ %val4, %then ], [ %val3, %else ]
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ret i32 %ret
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}
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define i32 @zero1(i32 %i, i32 %a, i32 %b) {
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; CHECK: Printing analysis {{.*}} for function 'zero1'
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entry:
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%cond = icmp eq i32 %i, 0
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br i1 %cond, label %then, label %else
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; CHECK: edge entry -> then probability is 12 / 32
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; CHECK: edge entry -> else probability is 20 / 32
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then:
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br label %exit
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else:
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br label %exit
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exit:
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%result = phi i32 [ %a, %then ], [ %b, %else ]
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ret i32 %result
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}
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define i32 @zero2(i32 %i, i32 %a, i32 %b) {
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; CHECK: Printing analysis {{.*}} for function 'zero2'
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entry:
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%cond = icmp ne i32 %i, -1
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br i1 %cond, label %then, label %else
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; CHECK: edge entry -> then probability is 20 / 32
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; CHECK: edge entry -> else probability is 12 / 32
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then:
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br label %exit
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else:
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br label %exit
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exit:
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%result = phi i32 [ %a, %then ], [ %b, %else ]
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ret i32 %result
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}
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