llvm-6502/test/CodeGen/X86/imul.ll
Michael Kuperstein 0906c8fc1c [X86] Reduce some 32-bit imuls into lea + shl
Reduce integer multiplication by a constant of the form k*2^c, where k is in {3,5,9} into a lea + shl. Previously it was only done for imulq on 64-bit platforms, but it makes sense for imull and 32-bit as well.

Differential Revision: http://reviews.llvm.org/D7196

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227308 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-28 14:08:22 +00:00

111 lines
2.0 KiB
LLVM

; RUN: llc < %s -mtriple=x86_64-pc-linux-gnu | FileCheck %s --check-prefix=X64
; RUN: llc < %s -mtriple=x86_64-pc-linux-gnux32 | FileCheck %s --check-prefix=X64
; RUN: llc < %s -mtriple=i686-pc-linux | FileCheck %s --check-prefix=X86
define i32 @mul4_32(i32 %A) {
; X64-LABEL: mul4_32:
; X64: leal
; X86-LABEL: mul4_32:
; X86: shll
%mul = mul i32 %A, 4
ret i32 %mul
}
define i64 @mul4_64(i64 %A) {
; X64-LABEL: mul4_64:
; X64: leaq
; X86-LABEL: mul4_64:
; X86: shldl
; X86: shll
%mul = mul i64 %A, 4
ret i64 %mul
}
define i32 @mul4096_32(i32 %A) {
; X64-LABEL: mul4096_32:
; X64: shll
; X86-LABEL: mul4096_32:
; X86: shll
%mul = mul i32 %A, 4096
ret i32 %mul
}
define i64 @mul4096_64(i64 %A) {
; X64-LABEL: mul4096_64:
; X64: shlq
; X86-LABEL: mul4096_64:
; X86: shldl
; X86: shll
%mul = mul i64 %A, 4096
ret i64 %mul
}
define i32 @mulmin4096_32(i32 %A) {
; X64-LABEL: mulmin4096_32:
; X64: shll
; X64-NEXT: negl
; X86-LABEL: mulmin4096_32:
; X86: shll
; X86-NEXT: negl
%mul = mul i32 %A, -4096
ret i32 %mul
}
define i64 @mulmin4096_64(i64 %A) {
; X64-LABEL: mulmin4096_64:
; X64: shlq
; X64-NEXT: negq
; X86-LABEL: mulmin4096_64:
; X86: shldl
; X86-NEXT: shll
; X86-NEXT: xorl
; X86-NEXT: negl
; X86-NEXT: sbbl
%mul = mul i64 %A, -4096
ret i64 %mul
}
define i32 @mul3_32(i32 %A) {
; X64-LABEL: mul3_32:
; X64: leal
; X86-LABEL: mul3_32:
; But why?!
; X86: imull
%mul = mul i32 %A, 3
ret i32 %mul
}
define i64 @mul3_64(i64 %A) {
; X64-LABEL: mul3_64:
; X64: leaq
; X86-LABEL: mul3_64:
; X86: mull
; X86-NEXT: imull
%mul = mul i64 %A, 3
ret i64 %mul
}
define i32 @mul40_32(i32 %A) {
; X64-LABEL: mul40_32:
; X64: shll
; X64-NEXT: leal
; X86-LABEL: mul40_32:
; X86: shll
; X86-NEXT: leal
%mul = mul i32 %A, 40
ret i32 %mul
}
define i64 @mul40_64(i64 %A) {
; X64-LABEL: mul40_64:
; X64: shlq
; X64-NEXT: leaq
; X86-LABEL: mul40_64:
; X86: leal
; X86-NEXT: movl
; X86-NEXT: mull
; X86-NEXT: leal
%mul = mul i64 %A, 40
ret i64 %mul
}