llvm-6502/test/CodeGen/Mips/brdelayslot.ll
Akira Hatanaka 6ff59a16a0 [mips] Make sure loads from lazy-binding entries do not get CSE'd or hoisted out
of loops.

Previously, two consecutive calls to function "func" would result in the
following sequence of instructions:

1. load $16, %got(func)($gp) // load address of lazy-binding stub.
2. move $25, $16
3. jalr $25                  // jump to lazy-binding stub.
4. nop
5. move $25, $16
6. jalr $25                  // jump to lazy-binding stub again.

With this patch, the second call directly jumps to func's address, bypassing
the lazy-binding resolution routine:

1. load $25, %got(func)($gp) // load address of lazy-binding stub.
2. jalr $25                  // jump to lazy-binding stub.
3. nop
4. load $25, %got(func)($gp) // load resolved address of func.
5. jalr $25                  // directly jump to func.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191591 91177308-0d34-0410-b5e6-96231b3b80d8
2013-09-28 00:12:32 +00:00

186 lines
4.5 KiB
LLVM

; RUN: llc -march=mipsel -O0 < %s | FileCheck %s -check-prefix=None
; RUN: llc -march=mipsel < %s | FileCheck %s -check-prefix=Default
; RUN: llc -march=mipsel -O1 -relocation-model=static < %s | \
; RUN: FileCheck %s -check-prefix=STATICO1
; RUN: llc -march=mipsel -disable-mips-df-forward-search=false \
; RUN: -relocation-model=static < %s | FileCheck %s -check-prefix=FORWARD
; RUN: llc -march=mipsel -disable-mips-df-backward-search \
; RUN: -disable-mips-df-succbb-search=false < %s | \
; RUN: FileCheck %s -check-prefix=SUCCBB
define void @foo1() nounwind {
entry:
; Default: jalr
; Default-NOT: nop
; Default: jr
; Default-NOT: nop
; Default: .end
; None: jalr
; None: nop
; None: jr
; None: nop
; None: .end
tail call void @foo2(i32 3) nounwind
ret void
}
declare void @foo2(i32)
; Check that cvt.d.w goes into jalr's delay slot.
;
define void @foo3(i32 %a) nounwind {
entry:
; Default-LABEL: foo3:
; Default: jalr
; Default: cvt.d.w
%conv = sitofp i32 %a to double
tail call void @foo4(double %conv) nounwind
ret void
}
declare void @foo4(double)
@g2 = external global i32
@g1 = external global i32
@g3 = external global i32
; Check that branch delay slot can be filled with an instruction with operand
; $1.
;
; Default-LABEL: foo5:
; Default-NOT: nop
define void @foo5(i32 %a) nounwind {
entry:
%0 = load i32* @g2, align 4
%tobool = icmp eq i32 %a, 0
br i1 %tobool, label %if.else, label %if.then
if.then:
%1 = load i32* @g1, align 4
%add = add nsw i32 %1, %0
store i32 %add, i32* @g1, align 4
br label %if.end
if.else:
%2 = load i32* @g3, align 4
%sub = sub nsw i32 %2, %0
store i32 %sub, i32* @g3, align 4
br label %if.end
if.end:
ret void
}
; Check that delay slot filler can place mov.s or mov.d in delay slot.
;
; Default-LABEL: foo6:
; Default-NOT: nop
; Default: .end foo6
define void @foo6(float %a0, double %a1) nounwind {
entry:
tail call void @foo7(double %a1, float %a0) nounwind
ret void
}
declare void @foo7(double, float)
; Check that a store can move past other memory instructions.
;
; STATICO1-LABEL: foo8:
; STATICO1: jalr ${{[0-9]+}}
; STATICO1-NEXT: sw ${{[0-9]+}}, %lo(g1)
@foo9 = common global void ()* null, align 4
define i32 @foo8(i32 %a) nounwind {
entry:
store i32 %a, i32* @g1, align 4
%0 = load void ()** @foo9, align 4
tail call void %0() nounwind
%1 = load i32* @g1, align 4
%add = add nsw i32 %1, %a
ret i32 %add
}
; Test searchForward. Check that the second jal's slot is filled with another
; instruction in the same block.
;
; FORWARD-LABEL: foo10:
; FORWARD: jal foo11
; FORWARD: jal foo11
; FORWARD-NOT: nop
; FORWARD: end foo10
define void @foo10() nounwind {
entry:
tail call void @foo11() nounwind
tail call void @foo11() nounwind
store i32 0, i32* @g1, align 4
tail call void @foo11() nounwind
store i32 0, i32* @g1, align 4
ret void
}
declare void @foo11()
; Check that delay slots of branches in both the entry block and loop body are
; filled.
;
; SUCCBB-LABEL: succbbs_loop1:
; SUCCBB: blez $5, $BB
; SUCCBB-NEXT: addiu
; SUCCBB: bnez ${{[0-9]+}}, $BB
; SUCCBB-NEXT: addiu
define i32 @succbbs_loop1(i32* nocapture %a, i32 %n) {
entry:
%cmp4 = icmp sgt i32 %n, 0
br i1 %cmp4, label %for.body, label %for.end
for.body: ; preds = %entry, %for.body
%s.06 = phi i32 [ %add, %for.body ], [ 0, %entry ]
%i.05 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %a, i32 %i.05
%0 = load i32* %arrayidx, align 4
%add = add nsw i32 %0, %s.06
%inc = add nsw i32 %i.05, 1
%exitcond = icmp eq i32 %inc, %n
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body, %entry
%s.0.lcssa = phi i32 [ 0, %entry ], [ %add, %for.body ]
ret i32 %s.0.lcssa
}
; Check that the first branch has its slot filled.
;
; SUCCBB-LABEL: succbbs_br1:
; SUCCBB: beqz ${{[0-9]+}}, $BB
; SUCCBB-NEXT: lw ${{[0-9]+}}, %got(foo101)(${{[0-9]+}})
define internal fastcc void @foo101() {
entry:
tail call void @foo100()
tail call void @foo100()
ret void
}
define void @succbbs_br1(i32 %a) {
entry:
%tobool = icmp eq i32 %a, 0
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call fastcc void @foo101()
br label %if.end
if.end: ; preds = %entry, %if.then
ret void
}
declare void @foo100()