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659228b9db
Instead of always using addu to adjust the stack pointer when the size out is of the range of an addiu instruction, use subu so that a smaller constant can be generated. This can give savings of ~3 instructions whenever a function has a a stack frame whose size is out of range of an addiu instruction. This change may break some naive stack unwinders. Partially resolves PR/26291. Thanks to David Chisnall for reporting the issue. Reviewers: dsanders, vkalintiris Differential Review: http://reviews.llvm.org/D21321 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272666 91177308-0d34-0410-b5e6-96231b3b80d8
74 lines
1.7 KiB
LLVM
74 lines
1.7 KiB
LLVM
; RUN: llc -march=mipsel -mcpu=mips32 < %s | FileCheck %s
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; RUN: llc -march=mips64el -mcpu=mips4 < %s | \
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; RUN: FileCheck %s -check-prefix=CHECK-MIPS64
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; RUN: llc -march=mips64el -mcpu=mips64 < %s | \
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; RUN: FileCheck %s -check-prefix=CHECK-MIPS64
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declare i8* @llvm.eh.dwarf.cfa(i32) nounwind
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declare i8* @llvm.frameaddress(i32) nounwind readnone
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define i8* @f1() nounwind {
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entry:
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%x = alloca [32 x i8], align 1
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%0 = call i8* @llvm.eh.dwarf.cfa(i32 0)
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ret i8* %0
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; CHECK-LABEL: f1:
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; CHECK: addiu $sp, $sp, -32
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; CHECK: addiu $2, $sp, 32
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}
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define i8* @f2() nounwind {
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entry:
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%x = alloca [65536 x i8], align 1
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%0 = call i8* @llvm.eh.dwarf.cfa(i32 0)
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ret i8* %0
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; CHECK-LABEL: f2:
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; check stack size (65536 + 8)
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; CHECK: lui $[[R0:[a-z0-9]+]], 1
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; CHECK: addiu $[[R0]], $[[R0]], 8
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; CHECK: subu $sp, $sp, $[[R0]]
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; check return value ($sp + stack size)
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; CHECK: lui $[[R1:[a-z0-9]+]], 1
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; CHECK: addu $[[R1]], $sp, $[[R1]]
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; CHECK: addiu $2, $[[R1]], 8
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}
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define i32 @f3() nounwind {
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entry:
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%x = alloca [32 x i8], align 1
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%0 = call i8* @llvm.eh.dwarf.cfa(i32 0)
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%1 = ptrtoint i8* %0 to i32
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%2 = call i8* @llvm.frameaddress(i32 0)
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%3 = ptrtoint i8* %2 to i32
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%add = add i32 %1, %3
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ret i32 %add
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; CHECK-LABEL: f3:
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; CHECK: addiu $sp, $sp, -40
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; check return value ($fp + stack size + $fp)
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; CHECK: addiu $[[R0:[a-z0-9]+]], $fp, 40
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; CHECK: addu $2, $[[R0]], $fp
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}
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define i8* @f4() nounwind {
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entry:
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%x = alloca [32 x i8], align 1
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%0 = call i8* @llvm.eh.dwarf.cfa(i32 0)
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ret i8* %0
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; CHECK-LABEL: f4:
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; CHECK-MIPS64: daddiu $sp, $sp, -32
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; CHECK-MIPS64: daddiu $2, $sp, 32
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}
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