2017-02-07 00:21:41 +08:00
|
|
|
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
|
|
|
|
|
; RUN: llc < %s -mtriple=i386-unknown | FileCheck %s --check-prefix=X32
|
|
|
|
|
; RUN: llc < %s -mtriple=x86_64-unknown | FileCheck %s --check-prefix=X64
|
|
|
|
|
|
[SDAG] Add a fallback multiplication expansion
LegalizeIntegerTypes does not have a way to expand multiplications for large
integer types (i.e. larger than twice the native bit width). There's no
standard runtime call to use in that case, and so we'd just assert.
Unfortunately, as it turns out, it is possible to hit this case from
standard-ish C code in rare cases. A particular case a user ran into yesterday
involved an __int128 induction variable and a loop with a quadratic (not
linear) recurrence which triggered some backend logic using SCEVExpander. In
this case, the BinomialCoefficient code in SCEV generates some i129 variables,
which get widened to i256. At a high level, this is not actually good (i.e. the
underlying optimization, PPCLoopPreIncPrep, should not be transforming the loop
in question for performance reasons), but regardless, the backend shouldn't
crash because of cost-modeling issues in the optimizer.
This is a straightforward implementation of the multiplication expansion, based
on the algorithm in Hacker's Delight. I validated it against the code for the
mul256b function from http://locklessinc.com/articles/256bit_arithmetic/ using
random inputs. There should be no functional change for previously-working code
(the new expansion code only replaces an assert).
Fixes PR19797.
llvm-svn: 270720
2016-05-26 00:50:22 +08:00
|
|
|
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
|
|
|
|
|
target triple = "x86_64-unknown-linux-gnu"
|
|
|
|
|
|
|
|
|
|
define void @test(i256* %a, i256* %b, i256* %out) #0 {
|
2017-02-07 00:21:41 +08:00
|
|
|
; X32-LABEL: test:
|
|
|
|
|
; X32: # BB#0: # %entry
|
|
|
|
|
; X32-NEXT: pushl %ebp
|
|
|
|
|
; X32-NEXT: .Lcfi0:
|
|
|
|
|
; X32-NEXT: .cfi_def_cfa_offset 8
|
|
|
|
|
; X32-NEXT: .Lcfi1:
|
|
|
|
|
; X32-NEXT: .cfi_offset %ebp, -8
|
|
|
|
|
; X32-NEXT: movl %esp, %ebp
|
|
|
|
|
; X32-NEXT: .Lcfi2:
|
|
|
|
|
; X32-NEXT: .cfi_def_cfa_register %ebp
|
|
|
|
|
; X32-NEXT: pushl %ebx
|
|
|
|
|
; X32-NEXT: pushl %edi
|
|
|
|
|
; X32-NEXT: pushl %esi
|
|
|
|
|
; X32-NEXT: andl $-8, %esp
|
|
|
|
|
; X32-NEXT: subl $168, %esp
|
|
|
|
|
; X32-NEXT: .Lcfi3:
|
|
|
|
|
; X32-NEXT: .cfi_offset %esi, -20
|
|
|
|
|
; X32-NEXT: .Lcfi4:
|
|
|
|
|
; X32-NEXT: .cfi_offset %edi, -16
|
|
|
|
|
; X32-NEXT: .Lcfi5:
|
|
|
|
|
; X32-NEXT: .cfi_offset %ebx, -12
|
|
|
|
|
; X32-NEXT: movl 8(%ebp), %eax
|
|
|
|
|
; X32-NEXT: movl 16(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 20(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 24(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 28(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 8(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 12(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl (%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 4(%eax), %ebx
|
|
|
|
|
; X32-NEXT: movl 12(%ebp), %eax
|
|
|
|
|
; X32-NEXT: movl 16(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 20(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 24(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 28(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl (%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 4(%eax), %ecx
|
|
|
|
|
; X32-NEXT: movl %ecx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl 8(%eax), %esi
|
|
|
|
|
; X32-NEXT: movl 12(%eax), %edi
|
|
|
|
|
; X32-NEXT: leal {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl %edi
|
|
|
|
|
; X32-NEXT: movl %edi, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: pushl %esi
|
|
|
|
|
; X32-NEXT: movl %esi, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl %ebx
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl %eax
|
|
|
|
|
; X32-NEXT: calll __multi3
|
|
|
|
|
; X32-NEXT: addl $32, %esp
|
|
|
|
|
; X32-NEXT: leal {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl %edi
|
|
|
|
|
; X32-NEXT: pushl %esi
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %esi # 4-byte Reload
|
|
|
|
|
; X32-NEXT: pushl %esi
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi # 4-byte Reload
|
|
|
|
|
; X32-NEXT: pushl %edi
|
|
|
|
|
; X32-NEXT: pushl %eax
|
|
|
|
|
; X32-NEXT: calll __multi3
|
|
|
|
|
; X32-NEXT: addl $32, %esp
|
|
|
|
|
; X32-NEXT: leal {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl %ebx
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl %eax
|
|
|
|
|
; X32-NEXT: calll __multi3
|
|
|
|
|
; X32-NEXT: addl $32, %esp
|
|
|
|
|
; X32-NEXT: leal {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: pushl %esi
|
|
|
|
|
; X32-NEXT: pushl %edi
|
|
|
|
|
; X32-NEXT: pushl %ebx
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl %eax
|
|
|
|
|
; X32-NEXT: calll __multi3
|
|
|
|
|
; X32-NEXT: addl $32, %esp
|
|
|
|
|
; X32-NEXT: leal {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl $0
|
|
|
|
|
; X32-NEXT: pushl %esi
|
|
|
|
|
; X32-NEXT: pushl %edi
|
|
|
|
|
; X32-NEXT: pushl %eax
|
|
|
|
|
; X32-NEXT: calll __multi3
|
|
|
|
|
; X32-NEXT: addl $32, %esp
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %ecx
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edx
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %esi
|
|
|
|
|
; X32-NEXT: addl {{[0-9]+}}(%esp), %edx
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %esi
|
|
|
|
|
; X32-NEXT: adcl $0, %ecx
|
|
|
|
|
; X32-NEXT: adcl $0, %eax
|
|
|
|
|
; X32-NEXT: addl {{[0-9]+}}(%esp), %edx
|
|
|
|
|
; X32-NEXT: movl %edx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %esi
|
|
|
|
|
; X32-NEXT: movl %esi, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi
|
|
|
|
|
; X32-NEXT: adcl $0, %edi
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %ebx
|
|
|
|
|
; X32-NEXT: adcl $0, %ebx
|
|
|
|
|
; X32-NEXT: xorl %edx, %edx
|
|
|
|
|
; X32-NEXT: addl %ecx, %edi
|
|
|
|
|
; X32-NEXT: adcl %eax, %ebx
|
|
|
|
|
; X32-NEXT: adcl $0, %edx
|
|
|
|
|
; X32-NEXT: sbbl %eax, %eax
|
|
|
|
|
; X32-NEXT: andl $1, %eax
|
|
|
|
|
; X32-NEXT: addl {{[0-9]+}}(%esp), %edi
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %ebx
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %edx
|
|
|
|
|
; X32-NEXT: movl %edx, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: movl %eax, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: leal {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl {{[0-9]+}}(%esp) # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: pushl %eax
|
|
|
|
|
; X32-NEXT: calll __multi3
|
|
|
|
|
; X32-NEXT: addl $32, %esp
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %esi
|
|
|
|
|
; X32-NEXT: addl {{[0-9]+}}(%esp), %esi
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %ecx
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %ecx
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edx
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %edx
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %eax
|
|
|
|
|
; X32-NEXT: addl %edi, %esi
|
|
|
|
|
; X32-NEXT: adcl %ebx, %ecx
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %edx # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: adcl {{[0-9]+}}(%esp), %eax # 4-byte Folded Reload
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi
|
|
|
|
|
; X32-NEXT: movl %edi, {{[0-9]+}}(%esp) # 4-byte Spill
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %ebx
|
|
|
|
|
; X32-NEXT: movl 16(%ebp), %edi
|
|
|
|
|
; X32-NEXT: movl %ebx, 4(%edi)
|
|
|
|
|
; X32-NEXT: movl 16(%ebp), %ebx
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi # 4-byte Reload
|
|
|
|
|
; X32-NEXT: movl %edi, (%ebx)
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi # 4-byte Reload
|
|
|
|
|
; X32-NEXT: movl %edi, 8(%ebx)
|
|
|
|
|
; X32-NEXT: movl {{[0-9]+}}(%esp), %edi # 4-byte Reload
|
|
|
|
|
; X32-NEXT: movl %edi, 12(%ebx)
|
|
|
|
|
; X32-NEXT: movl %esi, 16(%ebx)
|
|
|
|
|
; X32-NEXT: movl %ecx, 20(%ebx)
|
|
|
|
|
; X32-NEXT: movl %edx, 24(%ebx)
|
|
|
|
|
; X32-NEXT: movl %eax, 28(%ebx)
|
|
|
|
|
; X32-NEXT: leal -12(%ebp), %esp
|
|
|
|
|
; X32-NEXT: popl %esi
|
|
|
|
|
; X32-NEXT: popl %edi
|
|
|
|
|
; X32-NEXT: popl %ebx
|
|
|
|
|
; X32-NEXT: popl %ebp
|
|
|
|
|
; X32-NEXT: retl
|
|
|
|
|
;
|
|
|
|
|
; X64-LABEL: test:
|
|
|
|
|
; X64: # BB#0: # %entry
|
|
|
|
|
; X64-NEXT: pushq %r15
|
|
|
|
|
; X64-NEXT: .Lcfi0:
|
|
|
|
|
; X64-NEXT: .cfi_def_cfa_offset 16
|
|
|
|
|
; X64-NEXT: pushq %r14
|
|
|
|
|
; X64-NEXT: .Lcfi1:
|
|
|
|
|
; X64-NEXT: .cfi_def_cfa_offset 24
|
|
|
|
|
; X64-NEXT: pushq %r12
|
|
|
|
|
; X64-NEXT: .Lcfi2:
|
|
|
|
|
; X64-NEXT: .cfi_def_cfa_offset 32
|
|
|
|
|
; X64-NEXT: pushq %rbx
|
|
|
|
|
; X64-NEXT: .Lcfi3:
|
|
|
|
|
; X64-NEXT: .cfi_def_cfa_offset 40
|
|
|
|
|
; X64-NEXT: .Lcfi4:
|
|
|
|
|
; X64-NEXT: .cfi_offset %rbx, -40
|
|
|
|
|
; X64-NEXT: .Lcfi5:
|
|
|
|
|
; X64-NEXT: .cfi_offset %r12, -32
|
|
|
|
|
; X64-NEXT: .Lcfi6:
|
|
|
|
|
; X64-NEXT: .cfi_offset %r14, -24
|
|
|
|
|
; X64-NEXT: .Lcfi7:
|
|
|
|
|
; X64-NEXT: .cfi_offset %r15, -16
|
|
|
|
|
; X64-NEXT: movq %rdx, %r10
|
|
|
|
|
; X64-NEXT: movq (%rdi), %r14
|
|
|
|
|
; X64-NEXT: movq 8(%rdi), %r8
|
|
|
|
|
; X64-NEXT: movq 16(%rdi), %rcx
|
|
|
|
|
; X64-NEXT: movq 16(%rsi), %rbx
|
|
|
|
|
; X64-NEXT: movq (%rsi), %r12
|
|
|
|
|
; X64-NEXT: movq 8(%rsi), %r15
|
|
|
|
|
; X64-NEXT: movq 24(%rdi), %rdi
|
|
|
|
|
; X64-NEXT: imulq %r12, %rdi
|
|
|
|
|
; X64-NEXT: movq %r12, %rax
|
|
|
|
|
; X64-NEXT: mulq %rcx
|
|
|
|
|
; X64-NEXT: movq %rax, %r9
|
|
|
|
|
; X64-NEXT: addq %rdi, %rdx
|
|
|
|
|
; X64-NEXT: imulq %r15, %rcx
|
|
|
|
|
; X64-NEXT: addq %rdx, %rcx
|
|
|
|
|
; X64-NEXT: movq %rbx, %rdi
|
|
|
|
|
; X64-NEXT: imulq %r8, %rdi
|
|
|
|
|
; X64-NEXT: movq %rbx, %rax
|
|
|
|
|
; X64-NEXT: mulq %r14
|
|
|
|
|
; X64-NEXT: movq %rax, %r11
|
|
|
|
|
; X64-NEXT: addq %rdi, %rdx
|
|
|
|
|
; X64-NEXT: movq 24(%rsi), %rbx
|
|
|
|
|
; X64-NEXT: imulq %r14, %rbx
|
|
|
|
|
; X64-NEXT: addq %rdx, %rbx
|
|
|
|
|
; X64-NEXT: addq %r9, %r11
|
|
|
|
|
; X64-NEXT: adcq %rcx, %rbx
|
|
|
|
|
; X64-NEXT: movq %r14, %rax
|
|
|
|
|
; X64-NEXT: mulq %r12
|
|
|
|
|
; X64-NEXT: movq %rdx, %rsi
|
|
|
|
|
; X64-NEXT: movq %rax, %r9
|
|
|
|
|
; X64-NEXT: movq %r8, %rax
|
|
|
|
|
; X64-NEXT: mulq %r12
|
|
|
|
|
; X64-NEXT: movq %rdx, %rcx
|
|
|
|
|
; X64-NEXT: movq %rax, %rdi
|
|
|
|
|
; X64-NEXT: addq %rsi, %rdi
|
|
|
|
|
; X64-NEXT: adcq $0, %rcx
|
|
|
|
|
; X64-NEXT: movq %r14, %rax
|
|
|
|
|
; X64-NEXT: mulq %r15
|
|
|
|
|
; X64-NEXT: movq %rdx, %rsi
|
|
|
|
|
; X64-NEXT: movq %rax, %r14
|
|
|
|
|
; X64-NEXT: addq %rdi, %r14
|
|
|
|
|
; X64-NEXT: adcq $0, %rsi
|
|
|
|
|
; X64-NEXT: addq %rcx, %rsi
|
|
|
|
|
; X64-NEXT: sbbq %rcx, %rcx
|
|
|
|
|
; X64-NEXT: andl $1, %ecx
|
|
|
|
|
; X64-NEXT: movq %r8, %rax
|
|
|
|
|
; X64-NEXT: mulq %r15
|
|
|
|
|
; X64-NEXT: addq %rsi, %rax
|
|
|
|
|
; X64-NEXT: adcq %rcx, %rdx
|
|
|
|
|
; X64-NEXT: addq %r11, %rax
|
|
|
|
|
; X64-NEXT: adcq %rbx, %rdx
|
|
|
|
|
; X64-NEXT: movq %r9, (%r10)
|
|
|
|
|
; X64-NEXT: movq %r14, 8(%r10)
|
|
|
|
|
; X64-NEXT: movq %rax, 16(%r10)
|
|
|
|
|
; X64-NEXT: movq %rdx, 24(%r10)
|
|
|
|
|
; X64-NEXT: popq %rbx
|
|
|
|
|
; X64-NEXT: popq %r12
|
|
|
|
|
; X64-NEXT: popq %r14
|
|
|
|
|
; X64-NEXT: popq %r15
|
|
|
|
|
; X64-NEXT: retq
|
[SDAG] Add a fallback multiplication expansion
LegalizeIntegerTypes does not have a way to expand multiplications for large
integer types (i.e. larger than twice the native bit width). There's no
standard runtime call to use in that case, and so we'd just assert.
Unfortunately, as it turns out, it is possible to hit this case from
standard-ish C code in rare cases. A particular case a user ran into yesterday
involved an __int128 induction variable and a loop with a quadratic (not
linear) recurrence which triggered some backend logic using SCEVExpander. In
this case, the BinomialCoefficient code in SCEV generates some i129 variables,
which get widened to i256. At a high level, this is not actually good (i.e. the
underlying optimization, PPCLoopPreIncPrep, should not be transforming the loop
in question for performance reasons), but regardless, the backend shouldn't
crash because of cost-modeling issues in the optimizer.
This is a straightforward implementation of the multiplication expansion, based
on the algorithm in Hacker's Delight. I validated it against the code for the
mul256b function from http://locklessinc.com/articles/256bit_arithmetic/ using
random inputs. There should be no functional change for previously-working code
(the new expansion code only replaces an assert).
Fixes PR19797.
llvm-svn: 270720
2016-05-26 00:50:22 +08:00
|
|
|
entry:
|
|
|
|
|
%av = load i256, i256* %a
|
|
|
|
|
%bv = load i256, i256* %b
|
|
|
|
|
%r = mul i256 %av, %bv
|
|
|
|
|
store i256 %r, i256* %out
|
|
|
|
|
ret void
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
attributes #0 = { norecurse nounwind uwtable "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" }
|