f3718a9bf1
Summary:
With this patch, llgo uses ssautil.Switches
to reconstitute (and synthesise) switches,
which can then be lowered to lookup tables,
trees, etc.
We currently only handle integer const case
switches. We erase the comparison blocks (other
than the initial block), and generate a switch
instruction at the end of the block starting
the if-else-if chain. ssautil.Switches does
not remove duplicate const cases (e.g. same
operands for "||"), so we do this in llgo for
now.
Test Plan: lit test added
Reviewers: pcc
Reviewed By: pcc
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D6831
llvm-svn: 225433
63 lines
1.1 KiB
Go
63 lines
1.1 KiB
Go
// RUN: llgo -S -emit-llvm -o - %s | FileCheck %s
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package foo
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// CHECK: switch i32
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// CHECK-NEXT: i32 0, label %[[L0:.*]]
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// CHECK-NEXT: i32 1, label %[[L1:.*]]
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// CHECK-NEXT: i32 2, label %[[L2:.*]]
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// CHECK-NEXT: ]
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// CHECK: [[L0]]:
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// CHECK-NEXT: ret i32 1
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// CHECK: [[L1]]:
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// CHECK-NEXT: ret i32 2
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// CHECK: [[L2]]:
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// CHECK-NEXT: ret i32 0
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func F1(x int32) int32 {
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switch x {
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case 0:
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return 1
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case 1:
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return 2
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case 2:
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return 0
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}
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panic("unreachable")
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}
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// CHECK: switch i64
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// CHECK-NEXT: i64 0
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// CHECK-NEXT: ]
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// CHECK: icmp eq i64 {{.*}}, 1
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func F2(x int64) bool {
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return x == 0 || x == 0 || x == 1
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}
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// CHECK: switch i64
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// CHECK-NEXT: i64 0
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// CHECK-NEXT: ]
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func F3(x int64) bool {
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return x == 0 || x == 0 || x == 0
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}
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// CHECK: switch i64
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// CHECK-NEXT: i64 0
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// CHECK-NEXT: i64 1
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// CHECK-NEXT: i64 2
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// CHECK-NEXT: ]
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// CHECK: icmp eq i64 {{.*}}, 3
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func F4(x int64) bool {
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return x == 0 || x == 1 || x == 2 || x == 3
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}
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// CHECK-NOT: switch double
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func F5(x float64) float64 {
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switch x {
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case 0:
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return 1.0
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case 1.0:
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return 0
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}
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panic("unreachable")
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}
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