llvm-6502/test/CodeGen/X86/2013-10-14-FastISel-incorrect-vreg.ll
Hans Wennborg a421ac689f SelectionDAG switch lowering: Replace unreachable default with most popular case.
This can significantly reduce the size of the switch, allowing for more
efficient lowering.

I also worked with the idea of exploiting unreachable defaults by
omitting the range check for jump tables, but always ended up with a
non-neglible binary size increase. It might be worth looking into some more.

SimplifyCFG currently does this transformation, but I'm working towards changing
that so we can optimize harder based on unreachable defaults.

Differential Revision: http://reviews.llvm.org/D6510

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223566 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-06 01:28:50 +00:00

133 lines
3.9 KiB
LLVM

; RUN: llc -mtriple x86_64-apple-darwin -O0 < %s -o - | FileCheck %s
;
; During X86 fastisel, the address of indirect call was resolved
; through bitcast, ptrtoint, and inttoptr instructions. This is valid
; only if the related instructions are in that same basic block, otherwise
; we may reference variables that were not live across basic blocks
; resulting in undefined virtual registers.
;
; In this example, this is illustrated by a spill/reload of the
; LOADED_PTR_SLOT.
;
; Before this patch, the compiler was accessing two different spill
; slots.
; <rdar://problem/15192473>
; CHECK-LABEL: @test_bitcast
; Load the value of the function pointer: %loaded_ptr
; CHECK: movq (%rdi), [[LOADED_PTR:%[a-z]+]]
; Spill %arg2.
; CHECK: movq %rdx, [[ARG2_SLOT:[0-9]*\(%[a-z]+\)]]
; Spill %loaded_ptr.
; CHECK: movq [[LOADED_PTR]], [[LOADED_PTR_SLOT:[0-9]*\(%[a-z]+\)]]
; Perform the indirect call.
; Load the first argument
; CHECK: movq [[ARG2_SLOT]], %rdi
; Load the second argument
; CHECK: movq [[ARG2_SLOT]], %rsi
; Load the third argument
; CHECK: movq [[ARG2_SLOT]], %rdx
; Load the function pointer.
; CHECK: movq [[LOADED_PTR_SLOT]], [[FCT_PTR:%[a-z]+]]
; Call.
; CHECK: callq *[[FCT_PTR]]
; CHECK: ret
define i64 @test_bitcast(i64 (i64, i64, i64)** %arg, i1 %bool, i64 %arg2) {
entry:
%loaded_ptr = load i64 (i64, i64, i64)** %arg, align 8
%raw = bitcast i64 (i64, i64, i64)* %loaded_ptr to i8*
switch i1 %bool, label %default [
i1 true, label %label_true
i1 false, label %label_end
]
default:
br label %label_end
label_true:
br label %label_end
label_end:
%fct_ptr = bitcast i8* %raw to i64 (i64, i64, i64)*
%res = call i64 %fct_ptr(i64 %arg2, i64 %arg2, i64 %arg2)
ret i64 %res
}
; CHECK-LABEL: @test_inttoptr
; Load the value of the function pointer: %loaded_ptr
; CHECK: movq (%rdi), [[LOADED_PTR:%[a-z]+]]
; Spill %arg2.
; CHECK: movq %rdx, [[ARG2_SLOT:[0-9]*\(%[a-z]+\)]]
; Spill %loaded_ptr.
; CHECK: movq [[LOADED_PTR]], [[LOADED_PTR_SLOT:[0-9]*\(%[a-z]+\)]]
; Perform the indirect call.
; Load the first argument
; CHECK: movq [[ARG2_SLOT]], %rdi
; Load the second argument
; CHECK: movq [[ARG2_SLOT]], %rsi
; Load the third argument
; CHECK: movq [[ARG2_SLOT]], %rdx
; Load the function pointer.
; CHECK: movq [[LOADED_PTR_SLOT]], [[FCT_PTR:%[a-z]+]]
; Call.
; CHECK: callq *[[FCT_PTR]]
; CHECK: ret
define i64 @test_inttoptr(i64 (i64, i64, i64)** %arg, i1 %bool, i64 %arg2) {
entry:
%loaded_ptr = load i64 (i64, i64, i64)** %arg, align 8
%raw = ptrtoint i64 (i64, i64, i64)* %loaded_ptr to i64
switch i1 %bool, label %default [
i1 true, label %label_true
i1 false, label %label_end
]
default:
br label %label_end
label_true:
br label %label_end
label_end:
%fct_ptr = inttoptr i64 %raw to i64 (i64, i64, i64)*
%res = call i64 %fct_ptr(i64 %arg2, i64 %arg2, i64 %arg2)
ret i64 %res
}
; CHECK-LABEL: @test_ptrtoint
; Load the value of the function pointer: %loaded_ptr
; CHECK: movq (%rdi), [[LOADED_PTR:%[a-z]+]]
; Spill %arg2.
; CHECK: movq %rdx, [[ARG2_SLOT:[0-9]*\(%[a-z]+\)]]
; Spill %loaded_ptr.
; CHECK: movq [[LOADED_PTR]], [[LOADED_PTR_SLOT:[0-9]*\(%[a-z]+\)]]
; Perform the indirect call.
; Load the first argument
; CHECK: movq [[ARG2_SLOT]], %rdi
; Load the second argument
; CHECK: movq [[ARG2_SLOT]], %rsi
; Load the third argument
; CHECK: movq [[ARG2_SLOT]], %rdx
; Load the function pointer.
; CHECK: movq [[LOADED_PTR_SLOT]], [[FCT_PTR:%[a-z]+]]
; Call.
; CHECK: callq *[[FCT_PTR]]
; CHECK: ret
define i64 @test_ptrtoint(i64 (i64, i64, i64)** %arg, i1 %bool, i64 %arg2) {
entry:
%loaded_ptr = load i64 (i64, i64, i64)** %arg, align 8
%raw = bitcast i64 (i64, i64, i64)* %loaded_ptr to i8*
switch i1 %bool, label %default [
i1 true, label %label_true
i1 false, label %label_end
]
default:
br label %label_end
label_true:
br label %label_end
label_end:
%fct_int = ptrtoint i8* %raw to i64
%fct_ptr = inttoptr i64 %fct_int to i64 (i64, i64, i64)*
%res = call i64 %fct_ptr(i64 %arg2, i64 %arg2, i64 %arg2)
ret i64 %res
}