Fix frame pointer loads/stores in the ARM integrated assembler.

tests_lit/assembler/arm32/store-sf.ll

+; Sample program that generates "str reg, [fp, #CCCC]", to show that we

[Jim Stichnoth, 2015/11/11 20:42:09]

This test case seems vastly over-complicated.  How about this?

define internal void @test_vla_non_entry_block(i32 %n) {
entry:
  br label %next
next:
; Put the variable-length alloca in a non-entry block, to reduce the chance of
; the optimizer putting it before the regular frame creation.
  %v = alloca i8, i32 %n, align 4
  ret void
}

[Karl, 2015/11/11 22:42:57]

Done.

[Jim Stichnoth, 2015/11/11 23:12:27]

Could you add that comment to the function?  Specifically this:

; Put the variable-length alloca in a non-entry block, to reduce the chance of
; the optimizer putting it before the regular frame creation.

This may help future observers understand the choices made here.

+; recognize that "fp" should be used instead of "sp".
+
+; REQUIRES: allow_dump
+
+; Compile using standalone assembler.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --args -Om1 \
+; RUN:   -test-stack-extra=4088 | FileCheck %s --check-prefix=ASM
+
+; Show bytes in assembled standalone code.
+; RUN: %p2i --filetype=asm -i %s --target=arm32 --assemble --disassemble \
+; RUN:   --args -Om1 -test-stack-extra=4088 | FileCheck %s --check-prefix=DIS
+
+; Compile using integrated assembler.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --args -Om1 \
+; RUN:   -test-stack-extra=4088 -unsafe-ias | FileCheck %s --check-prefix=IASM
+
+; Show bytes in assembled integrated code.
+; RUN: %p2i --filetype=iasm -i %s --target=arm32 --assemble --disassemble \
+; RUN:   --args -Om1 -test-stack-extra=4088 -unsafe-ias \
+; RUN:   | FileCheck %s --check-prefix=DIS
+
+declare i8* @llvm.stacksave()
+
+declare void @llvm.stackrestore(i8*)
+
+define internal i32 @test_vla_in_loop(i32 %size, i32 %start, i32 %inc) {
+entry:
+  %cmp34 = icmp ult i32 %start, %size
+  br i1 %cmp34, label %for.body3.lr.ph, label %for.end16
+
+; ASM-LABEL: test_vla_in_loop:
+; ASM-NEXT: .Ltest_vla_in_loop$entry:
+; ASM-NEXT:     push    {fp, lr}
+; ASM:          mov     fp, sp
+; ASM:          movw    ip, #4248
+; ASM-NEXT:     sub     sp, sp, ip
+; ASM-NEXT:     str     r0, [fp, #-4092]
+
+; DIS-LABEL: 00000000 <test_vla_in_loop>:
+; DIS-NEXT:    0:       e92d4800
+; DIS-NEXT:    4:       e1a0b00d
+; DIS-NEXT:    8:       e301c098
+; DIS-NEXT:    c:       e04dd00c
+; DIS-NEXT:   10:       e50b0ffc
+
+; IASM-LABEL: test_vla_in_loop:
+; IASM-NEXT: .Ltest_vla_in_loop$entry:
+; IASM-NEXT:    .byte 0x0
+; IASM-NEXT:    .byte 0x48
+; IASM-NEXT:    .byte 0x2d
+; IASM-NEXT:    .byte 0xe9
+
+; IASM-NEXT:    .byte 0xd
+; IASM-NEXT:    .byte 0xb0
+; IASM-NEXT:    .byte 0xa0
+; IASM-NEXT:    .byte 0xe1
+
+; IASM-NEXT:    movw    ip, #4248
+; IASM-NEXT:    .byte 0xc
+; IASM-NEXT:    .byte 0xd0
+; IASM-NEXT:    .byte 0x4d
+; IASM-NEXT:    .byte 0xe0
+
+; IASM-NEXT:    .byte 0xfc
+; IASM-NEXT:    .byte 0xf
+; IASM-NEXT:    .byte 0xb
+; IASM-NEXT:    .byte 0xe5
+
+; NOTE: The remaining code is not tested.
+
+for.body3.lr.ph:                                  ; preds = %entry, %for.end13
+  %sum.036 = phi i32 [ %add10.lcssa, %for.end13 ], [ 0, %entry ]
+  %i.035 = phi i32 [ %inc15, %for.end13 ], [ %start, %entry ]
+  %sub = sub i32 %size, %i.035
+  %0 = call i8* @llvm.stacksave()
+  %vla.alloca_mul = mul i32 4, %sub
+  %vla = alloca i8, i32 %vla.alloca_mul, align 4
+  %vla.asint = ptrtoint i8* %vla to i32
+  br label %for.body3
+
+
+for.body3:                                        ; preds = %for.body3.lr.ph, %for.body3
+  %j.030 = phi i32 [ 0, %for.body3.lr.ph ], [ %inc4, %for.body3 ]
+  %mul = mul i32 %j.030, %start
+  %add = add i32 %mul, %inc
+  %call = call i32 @foo(i32 %add)
+  %gep_array = mul i32 %j.030, 4
+  %gep = add i32 %vla.asint, %gep_array
+  %gep.asptr = inttoptr i32 %gep to i32*
+  store i32 %call, i32* %gep.asptr, align 1
+  %inc4 = add i32 %j.030, 1
+  %cmp2 = icmp ult i32 %inc4, %sub
+  br i1 %cmp2, label %for.body3, label %for.body8
+
+for.body8:                                        ; preds = %for.body3, %for.body8
+  %j5.033 = phi i32 [ %inc12, %for.body8 ], [ 0, %for.body3 ]
+  %sum.132 = phi i32 [ %add10, %for.body8 ], [ %sum.036, %for.body3 ]
+  %gep_array2 = mul i32 %j5.033, 4
+  %gep3 = add i32 %vla.asint, %gep_array2
+  %gep3.asptr = inttoptr i32 %gep3 to i32*
+  %1 = load i32, i32* %gep3.asptr, align 1
+  %add10 = add i32 %1, %sum.132
+  %inc12 = add i32 %j5.033, 1
+  %cmp7 = icmp ult i32 %inc12, %sub
+  br i1 %cmp7, label %for.body8, label %for.end13
+
+for.end13:                                        ; preds = %for.body8
+  %add10.lcssa = phi i32 [ %add10, %for.body8 ]
+  call void @llvm.stackrestore(i8* %0)
+  %inc15 = add i32 %i.035, 1
+  %exitcond = icmp eq i32 %inc15, %size
+  br i1 %exitcond, label %for.end16, label %for.body3.lr.ph
+
+for.end16:                                        ; preds = %for.end13, %entry
+  %sum.0.lcssa = phi i32 [ 0, %entry ], [ %add10.lcssa, %for.end13 ]
+  ret i32 %sum.0.lcssa
+}
+
+define internal i32 @foo(i32 %x) {
+entry:
+  %mul = mul i32 %x, %x
+  ret i32 %mul
+}