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648f00c2f0
reserving a physical register ($gp or $28) for that purpose. This will completely eliminate loads that restore the value of $gp after every function call, if the register allocator assigns a callee-saved register, or eliminate unnecessary loads if it assigns a temporary register. example: .cpload $25 // set $gp. ... .cprestore 16 // store $gp to stack slot 16($sp). ... jalr $25 // function call. clobbers $gp. lw $gp, 16($sp) // not emitted if callee-saved reg is chosen. ... lw $2, 4($gp) ... jalr $25 // function call. lw $gp, 16($sp) // not emitted if $gp is not live after this instruction. ... git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151402 91177308-0d34-0410-b5e6-96231b3b80d8
23 lines
611 B
LLVM
23 lines
611 B
LLVM
; RUN: llc < %s -march=mipsel -mips-fix-global-base-reg=false | FileCheck %s
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@g0 = external global i32
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@g1 = external global i32
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@g2 = external global i32
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define void @foo1() nounwind {
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entry:
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; CHECK-NOT: .cpload
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; CHECK-NOT: .cprestore
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; CHECK: lui $[[R0:[0-9]+]], %hi(_gp_disp)
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; CHECK: addiu $[[R1:[0-9]+]], $[[R0]], %lo(_gp_disp)
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; CHECK: addu $[[GP:[0-9]+]], $[[R1]], $25
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; CHECK: lw ${{[0-9]+}}, %call16(foo2)($[[GP]])
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tail call void @foo2(i32* @g0) nounwind
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tail call void @foo2(i32* @g1) nounwind
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tail call void @foo2(i32* @g2) nounwind
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ret void
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}
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declare void @foo2(i32*)
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