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llvm-mirror/test/CodeGen/PowerPC/mcm-5.ll
Joerg Sonnenberger 846d981bf6 Always use relative jump table encodings on PowerPC64.
For the default, small and medium code model, use the existing
difference from the jump table towards the label. For all other code
models, setup the picbase and use the difference between the picbase and
the block address.

Overall, this results in smaller data tables at the expensive of one or
two more arithmetic operation at the jump site. Given that we only create
jump tables with a lot more than two entries, it is a net win in size.
For larger code models the assumption remains that individual functions
are no larger than 2GB.

Differential Revision: https://reviews.llvm.org/D26336

llvm-svn: 287059
2016-11-16 00:37:30 +00:00

80 lines
2.7 KiB
LLVM

; RUN: llc -verify-machineinstrs -mcpu=pwr7 -code-model=medium <%s | FileCheck %s
; RUN: llc -verify-machineinstrs -mcpu=pwr7 -code-model=large <%s | FileCheck -check-prefix=LARGE %s
; Test correct code generation for medium and large code model
; for loading the address of a jump table from the TOC.
target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"
define signext i32 @test_jump_table(i32 signext %i) nounwind {
entry:
%i.addr = alloca i32, align 4
store i32 %i, i32* %i.addr, align 4
%0 = load i32, i32* %i.addr, align 4
switch i32 %0, label %sw.default [
i32 3, label %sw.bb
i32 4, label %sw.bb1
i32 5, label %sw.bb2
i32 6, label %sw.bb3
]
sw.default: ; preds = %entry
br label %sw.epilog
sw.bb: ; preds = %entry
%1 = load i32, i32* %i.addr, align 4
%mul = mul nsw i32 %1, 7
store i32 %mul, i32* %i.addr, align 4
br label %sw.bb1
sw.bb1: ; preds = %entry, %sw.bb
%2 = load i32, i32* %i.addr, align 4
%dec = add nsw i32 %2, -1
store i32 %dec, i32* %i.addr, align 4
br label %sw.bb2
sw.bb2: ; preds = %entry, %sw.bb1
%3 = load i32, i32* %i.addr, align 4
%add = add nsw i32 %3, 3
store i32 %add, i32* %i.addr, align 4
br label %sw.bb3
sw.bb3: ; preds = %entry, %sw.bb2
%4 = load i32, i32* %i.addr, align 4
%shl = shl i32 %4, 1
store i32 %shl, i32* %i.addr, align 4
br label %sw.epilog
sw.epilog: ; preds = %sw.bb3, %sw.default
%5 = load i32, i32* %i.addr, align 4
ret i32 %5
}
; CHECK-LABEL: test_jump_table:
; CHECK-NOT: bl .L0$pb
; CHECK: addis [[REG1:[0-9]+]], 2, .LC[[TOCNUM:[0-9]+]]@toc@ha
; CHECK: ld [[REG2:[0-9]+]], .LC[[TOCNUM]]@toc@l([[REG1]])
; CHECK: lwax [[REG3:[0-9]+]], {{[0-9]+}}, [[REG2]]
; CHECK-NEXT: add [[REG4:[0-9]+]], [[REG3]], [[REG2]]
; CHECK-NEXT: mtctr [[REG4]]
; CHECK-NEXT: bctr
; CHECK-LABEL: .LJTI0_0:
; CHECK-NEXT: .long .LBB0_{{[0-9]+}}-.LJTI0_0
; LARGE-LABEL: test_jump_table:
; LARGE: bl .L0$pb
; LARGE-NEXT: .L0$pb:
; LARGE: mflr [[REGBASE:[0-9]+]]
; LARGE: addis [[REG1:[0-9]+]], 2, .LC[[TOCNUM:[0-9]+]]@toc@ha
; LARGE: ld [[REG2:[0-9]+]], .LC[[TOCNUM]]@toc@l([[REG1]])
; LARGE: lwax [[REG3:[0-9]+]], {{[0-9]+}}, [[REG2]]
; LARGE-NEXT: add [[REG4:[0-9]+]], [[REG3]], [[REGBASE]]
; LARGE-NEXT: mtctr [[REG4]]
; LARGE-NEXT: bctr
; LARGE-LABEL: .LJTI0_0:
; LARGE-NEXT: .long .LBB0_{{[0-9]+}}-.L0$pb