From 35188eb54db0df31a11bc2227292170d987efe1a Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sun, 15 Feb 2009 23:24:52 +0000 Subject: [PATCH] MachineLICM now handles these cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64620 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/README.txt | 85 --------------------------------------- 1 file changed, 85 deletions(-) diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 2b867f4d8dc..9a380acc6b7 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -233,97 +233,12 @@ Optimize copysign(x, *y) to use an integer load from y. //===---------------------------------------------------------------------===// -%X = weak global int 0 - -void %foo(int %N) { - %N = cast int %N to uint - %tmp.24 = setgt int %N, 0 - br bool %tmp.24, label %no_exit, label %return - -no_exit: - %indvar = phi uint [ 0, %entry ], [ %indvar.next, %no_exit ] - %i.0.0 = cast uint %indvar to int - volatile store int %i.0.0, int* %X - %indvar.next = add uint %indvar, 1 - %exitcond = seteq uint %indvar.next, %N - br bool %exitcond, label %return, label %no_exit - -return: - ret void -} - -compiles into: - - .text - .align 4 - .globl _foo -_foo: - movl 4(%esp), %eax - cmpl $1, %eax - jl LBB_foo_4 # return -LBB_foo_1: # no_exit.preheader - xorl %ecx, %ecx -LBB_foo_2: # no_exit - movl L_X$non_lazy_ptr, %edx - movl %ecx, (%edx) - incl %ecx - cmpl %eax, %ecx - jne LBB_foo_2 # no_exit -LBB_foo_3: # return.loopexit -LBB_foo_4: # return - ret - -We should hoist "movl L_X$non_lazy_ptr, %edx" out of the loop after -remateralization is implemented. This can be accomplished with 1) a target -dependent LICM pass or 2) makeing SelectDAG represent the whole function. - -//===---------------------------------------------------------------------===// - The following tests perform worse with LSR: lambda, siod, optimizer-eval, ackermann, hash2, nestedloop, strcat, and Treesor. //===---------------------------------------------------------------------===// -We are generating far worse code than gcc: - -volatile short X, Y; - -void foo(int N) { - int i; - for (i = 0; i < N; i++) { X = i; Y = i*4; } -} - -LBB1_1: # entry.bb_crit_edge - xorl %ecx, %ecx - xorw %dx, %dx -LBB1_2: # bb - movl L_X$non_lazy_ptr, %esi - movw %cx, (%esi) - movl L_Y$non_lazy_ptr, %esi - movw %dx, (%esi) - addw $4, %dx - incl %ecx - cmpl %eax, %ecx - jne LBB1_2 # bb - -vs. - - xorl %edx, %edx - movl L_X$non_lazy_ptr-"L00000000001$pb"(%ebx), %esi - movl L_Y$non_lazy_ptr-"L00000000001$pb"(%ebx), %ecx -L4: - movw %dx, (%esi) - leal 0(,%edx,4), %eax - movw %ax, (%ecx) - addl $1, %edx - cmpl %edx, %edi - jne L4 - -This is due to the lack of post regalloc LICM. - -//===---------------------------------------------------------------------===// - Teach the coalescer to coalesce vregs of different register classes. e.g. FR32 / FR64 to VR128. -- 2.34.1