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llvm-mirror/test/CodeGen/X86/loop-strength-reduce8.ll
Jingyue Wu 3ee10fc280 [MachineSink] Use the real post dominator tree
Summary:
Fixes a FIXME in MachineSinking. Instead of using the simple heuristics in
isPostDominatedBy, use the real MachinePostDominatorTree and MachineLoopInfo.
The old heuristics caused instructions to sink unnecessarily, and might create
register pressure.

This is the second try of the fix. The first one (D4814) caused a performance
regression due to failing to sink instructions out of loops (PR21115). This
patch fixes PR21115 by sinking an instruction from a deeper loop to a shallower
one regardless of whether the target block post-dominates the source.

Thanks Alexey Volkov for reporting PR21115! 

Test Plan:
Added a NVPTX codegen test to verify that our change prevents the backend from
over-sinking. It also shows the unnecessary register pressure caused by
over-sinking.

Added an X86 test to verify we can sink instructions out of loops regardless of
the dominance relationship. This test is reduced from Alexey's test in PR21115.

Updated an affected test in X86.

Also ran SPEC CINT2006 and llvm-test-suite for compilation time and runtime
performance. Results are attached separately in the review thread.

Reviewers: Jiangning, resistor, hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, bruno, volkalexey, llvm-commits, meheff, eliben, jholewinski

Differential Revision: http://reviews.llvm.org/D5633

llvm-svn: 219773
2014-10-15 03:27:43 +00:00

88 lines
7.2 KiB
LLVM

; RUN: llc < %s -mtriple=i386-apple-darwin | FileCheck %s
; FIXME: The first two instructions, movl and addl, should have been combined to
; "leal 16(%eax), %edx" by the backend (PR20776).
; CHECK: movl %eax, %edx
; CHECK: addl $16, %edx
; CHECK: align
; CHECK: addl $4, %edx
; CHECK: decl %ecx
; CHECK: jne LBB0_2
%struct.CUMULATIVE_ARGS = type { i32, i32, i32, i32, i32, i32, i32 }
%struct.bitmap_element = type { %struct.bitmap_element*, %struct.bitmap_element*, i32, [2 x i64] }
%struct.bitmap_head_def = type { %struct.bitmap_element*, %struct.bitmap_element*, i32 }
%struct.branch_path = type { %struct.rtx_def*, i32 }
%struct.c_lang_decl = type <{ i8, [3 x i8] }>
%struct.constant_descriptor = type { %struct.constant_descriptor*, i8*, %struct.rtx_def*, { x86_fp80 } }
%struct.eh_region = type { %struct.eh_region*, %struct.eh_region*, %struct.eh_region*, i32, %struct.bitmap_head_def*, i32, { { %struct.eh_region*, %struct.eh_region*, %struct.eh_region*, %struct.rtx_def* } }, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def* }
%struct.eh_status = type { %struct.eh_region*, %struct.eh_region**, %struct.eh_region*, %struct.eh_region*, %struct.tree_node*, %struct.rtx_def*, %struct.rtx_def*, i32, i32, %struct.varray_head_tag*, %struct.varray_head_tag*, %struct.varray_head_tag*, %struct.branch_path*, i32, i32, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def* }
%struct.emit_status = type { i32, i32, %struct.rtx_def*, %struct.rtx_def*, %struct.tree_node*, %struct.sequence_stack*, i32, i32, i8*, i32, i8*, %struct.tree_node**, %struct.rtx_def** }
%struct.equiv_table = type { %struct.rtx_def*, %struct.rtx_def* }
%struct.expr_status = type { i32, i32, i32, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def* }
%struct.function = type { %struct.eh_status*, %struct.stmt_status*, %struct.expr_status*, %struct.emit_status*, %struct.varasm_status*, i8*, %struct.tree_node*, %struct.function*, i32, i32, i32, i32, %struct.rtx_def*, %struct.CUMULATIVE_ARGS, %struct.rtx_def*, %struct.rtx_def*, i8*, %struct.initial_value_struct*, i32, %struct.tree_node*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.tree_node*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, %struct.rtx_def*, i64, %struct.tree_node*, %struct.tree_node*, %struct.rtx_def*, %struct.rtx_def*, i32, %struct.rtx_def**, %struct.temp_slot*, i32, i32, i32, %struct.var_refs_queue*, i32, i32, i8*, %struct.tree_node*, %struct.rtx_def*, i32, i32, %struct.machine_function*, i32, i32, %struct.language_function*, %struct.rtx_def*, i8, i8, i8 }
%struct.goto_fixup = type { %struct.goto_fixup*, %struct.rtx_def*, %struct.tree_node*, %struct.tree_node*, %struct.rtx_def*, i32, %struct.rtx_def*, %struct.tree_node* }
%struct.initial_value_struct = type { i32, i32, %struct.equiv_table* }
%struct.label_chain = type { %struct.label_chain*, %struct.tree_node* }
%struct.lang_decl = type { %struct.c_lang_decl, %struct.tree_node* }
%struct.language_function = type { %struct.stmt_tree_s, %struct.tree_node* }
%struct.machine_function = type { [59 x [3 x %struct.rtx_def*]], i32, i32 }
%struct.nesting = type { %struct.nesting*, %struct.nesting*, i32, %struct.rtx_def*, { { i32, %struct.rtx_def*, %struct.rtx_def*, %struct.nesting*, %struct.tree_node*, %struct.tree_node*, %struct.label_chain*, i32, i32, i32, i32, %struct.rtx_def*, %struct.tree_node** } } }
%struct.pool_constant = type { %struct.constant_descriptor*, %struct.pool_constant*, %struct.pool_constant*, %struct.rtx_def*, i32, i32, i32, i64, i32 }
%struct.rtunion = type { i64 }
%struct.rtx_def = type { i16, i8, i8, [1 x %struct.rtunion] }
%struct.sequence_stack = type { %struct.rtx_def*, %struct.rtx_def*, %struct.tree_node*, %struct.sequence_stack* }
%struct.stmt_status = type { %struct.nesting*, %struct.nesting*, %struct.nesting*, %struct.nesting*, %struct.nesting*, %struct.nesting*, i32, i32, %struct.tree_node*, %struct.rtx_def*, i32, i8*, i32, %struct.goto_fixup* }
%struct.stmt_tree_s = type { %struct.tree_node*, %struct.tree_node*, i8*, i32 }
%struct.temp_slot = type { %struct.temp_slot*, %struct.rtx_def*, %struct.rtx_def*, i32, i64, %struct.tree_node*, %struct.tree_node*, i8, i8, i32, i32, i64, i64 }
%struct.tree_common = type { %struct.tree_node*, %struct.tree_node*, i8, i8, i8, i8 }
%struct.tree_decl = type { %struct.tree_common, i8*, i32, i32, %struct.tree_node*, i8, i8, i8, i8, i8, i8, %struct.rtunion, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, %struct.rtx_def*, %struct.rtx_def*, { %struct.function* }, %struct.tree_node*, %struct.tree_node*, %struct.tree_node*, i64, %struct.lang_decl* }
%struct.tree_exp = type { %struct.tree_common, i32, [1 x %struct.tree_node*] }
%struct.tree_node = type { %struct.tree_decl }
%struct.var_refs_queue = type { %struct.rtx_def*, i32, i32, %struct.var_refs_queue* }
%struct.varasm_status = type { %struct.constant_descriptor**, %struct.pool_constant**, %struct.pool_constant*, %struct.pool_constant*, i64, %struct.rtx_def* }
%struct.varray_data = type { [1 x i64] }
%struct.varray_head_tag = type { i32, i32, i32, i8*, %struct.varray_data }
@lineno = internal global i32 0 ; <i32*> [#uses=1]
@tree_code_length = internal global [256 x i32] zeroinitializer
@llvm.used = appending global [1 x i8*] [ i8* bitcast (%struct.tree_node* (i32, ...)* @build_stmt to i8*) ], section "llvm.metadata" ; <[1 x i8*]*> [#uses=0]
define %struct.tree_node* @build_stmt(i32 %code, ...) nounwind {
entry:
%p = alloca i8* ; <i8**> [#uses=3]
%p1 = bitcast i8** %p to i8* ; <i8*> [#uses=2]
call void @llvm.va_start(i8* %p1)
%0 = call fastcc %struct.tree_node* @make_node(i32 %code) nounwind ; <%struct.tree_node*> [#uses=2]
%1 = getelementptr [256 x i32]* @tree_code_length, i32 0, i32 %code ; <i32*> [#uses=1]
%2 = load i32* %1, align 4 ; <i32> [#uses=2]
%3 = load i32* @lineno, align 4 ; <i32> [#uses=1]
%4 = bitcast %struct.tree_node* %0 to %struct.tree_exp* ; <%struct.tree_exp*> [#uses=2]
%5 = getelementptr %struct.tree_exp* %4, i32 0, i32 1 ; <i32*> [#uses=1]
store i32 %3, i32* %5, align 4
%6 = icmp sgt i32 %2, 0 ; <i1> [#uses=1]
br i1 %6, label %bb, label %bb3
bb: ; preds = %bb, %entry
%i.01 = phi i32 [ %indvar.next, %bb ], [ 0, %entry ] ; <i32> [#uses=2]
%7 = load i8** %p, align 4 ; <i8*> [#uses=2]
%8 = getelementptr i8* %7, i32 4 ; <i8*> [#uses=1]
store i8* %8, i8** %p, align 4
%9 = bitcast i8* %7 to %struct.tree_node** ; <%struct.tree_node**> [#uses=1]
%10 = load %struct.tree_node** %9, align 4 ; <%struct.tree_node*> [#uses=1]
%11 = getelementptr %struct.tree_exp* %4, i32 0, i32 2, i32 %i.01 ; <%struct.tree_node**> [#uses=1]
store %struct.tree_node* %10, %struct.tree_node** %11, align 4
%indvar.next = add i32 %i.01, 1 ; <i32> [#uses=2]
%exitcond = icmp eq i32 %indvar.next, %2 ; <i1> [#uses=1]
br i1 %exitcond, label %bb3, label %bb
bb3: ; preds = %bb, %entry
call void @llvm.va_end(i8* %p1)
ret %struct.tree_node* %0
}
declare void @llvm.va_start(i8*) nounwind
declare void @llvm.va_end(i8*) nounwind
declare fastcc %struct.tree_node* @make_node(i32) nounwind