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28f5cfb976
This branch adds hints for highly biased branches on the PPC architecture. Even in absence of profiling information, LLVM will mark code reaching unreachable terminators and other exceptional control flow constructs as highly unlikely to be reached. Patch by Tom Jablin! llvm-svn: 255398
136 lines
2.4 KiB
LLVM
136 lines
2.4 KiB
LLVM
; RUN: llc < %s -O1 -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -ppc-use-branch-hint=false | FileCheck %s
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; RUN: llc < %s -O1 -verify-machineinstrs -mtriple=powerpc64-unknown-linux-gnu -ppc-use-branch-hint=true | FileCheck %s -check-prefix=CHECK-HINT
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define void @branch_hint_1(i32 %src) {
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entry:
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%cmp = icmp eq i32 %src, 0
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br i1 %cmp, label %if.then, label %if.end
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if.then:
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tail call void @foo() #0
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unreachable
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if.end:
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call void @goo()
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ret void
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; CHECK-LABEL: branch_hint_1:
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; CHECK: beq
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; CHECK-HINT-LABEL: branch_hint_1:
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; CHECK-HINT: beq-
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}
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define void @branch_hint_2(i32 %src) {
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entry:
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%cmp = icmp eq i32 %src, 0
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br i1 %cmp, label %if.then, label %if.end
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if.then:
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call void @goo()
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ret void
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if.end:
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tail call void @foo() #0
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unreachable
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; CHECK-LABEL: @branch_hint_2
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; CHECK: bne
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; CHECK-HINT-LABEL: @branch_hint_2
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; CHECK-HINT: bne-
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}
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declare void @foo()
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attributes #0 = { noreturn }
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define void @branch_hint_3(i32 %src) {
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entry:
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%cmp = icmp eq i32 %src, 0
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br i1 %cmp, label %if.then, label %if.end, !prof !0
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if.then:
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call void @foo()
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ret void
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if.end:
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call void @goo()
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ret void
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; CHECK-LABEL: @branch_hint_3
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; CHECK: bne
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; CHECK-HINT-LABEL: @branch_hint_3
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; CHECK-HINT: bne
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}
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!0 = !{!"branch_weights", i32 64, i32 4}
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define void @branch_hint_4(i32 %src) {
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entry:
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%cmp = icmp eq i32 %src, 0
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br i1 %cmp, label %if.then, label %if.end, !prof !1
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if.then:
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call void @foo()
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ret void
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if.end:
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call void @goo()
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ret void
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; CHECK-HINT-LABEL: branch_hint_4
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; CHECK-HINT: bne
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}
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!1 = !{!"branch_weights", i32 64, i32 8}
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define void @branch_hint_5(i32 %src) {
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entry:
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%cmp = icmp eq i32 %src, 0
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br i1 %cmp, label %if.then, label %if.end
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if.then:
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ret void
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if.end:
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call void @goo()
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ret void
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; CHECK-HINT-LABEL: branch_hint_5:
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; CHECK-HINT: beq
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}
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declare void @goo()
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define void @branch_hint_6(i32 %src1, i32 %src2, i32 %src3) {
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entry:
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%cmp = icmp eq i32 %src1, 0
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br i1 %cmp, label %if.end.6, label %if.end, !prof !3
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if.end:
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%cmp1 = icmp eq i32 %src2, 0
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br i1 %cmp1, label %if.end.3, label %if.then.2
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if.then.2:
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tail call void @foo() #0
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unreachable
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if.end.3:
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%cmp4 = icmp eq i32 %src3, 1
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br i1 %cmp4, label %if.then.5, label %if.end.6
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if.then.5:
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tail call void @foo() #0
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unreachable
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if.end.6:
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ret void
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; CHECK-HINT-LABEL: branch_hint_6:
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; CHECK-HINT: bne
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; CHECK-HINT: bne-
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; CHECK-HINT: bne+
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}
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!3 = !{!"branch_weights", i32 64, i32 4}
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