llvm-6502/test/Transforms/StraightLineStrengthReduce/slsr-mul.ll
Jingyue Wu 439d17ca9f [SLSR] handle candidate form &B[i * S]
Summary:
This patch enhances SLSR to handle another candidate form &B[i * S]. If
we found two candidates

S1: X = &B[i * S]
S2: Y = &B[i' * S]

and S1 dominates S2, we can replace S2 with

Y = &X[(i' - i) * S]

Test Plan:
slsr-gep.ll
X86/no-slsr.ll: verify that we do not run SLSR on GEPs that already fit into
an addressing mode

Reviewers: eliben, atrick, meheff, hfinkel

Reviewed By: hfinkel

Subscribers: sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D7459

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233286 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-26 16:49:24 +00:00

122 lines
2.6 KiB
LLVM

; RUN: opt < %s -slsr -gvn -dce -S | FileCheck %s
target datalayout = "e-i64:64-v16:16-v32:32-n16:32:64"
declare i32 @foo(i32 %a)
define i32 @slsr1(i32 %b, i32 %s) {
; CHECK-LABEL: @slsr1(
; v0 = foo(b * s);
%mul0 = mul i32 %b, %s
; CHECK: mul i32
; CHECK-NOT: mul i32
%v0 = call i32 @foo(i32 %mul0)
; v1 = foo((b + 1) * s);
%b1 = add i32 %b, 1
%mul1 = mul i32 %b1, %s
%v1 = call i32 @foo(i32 %mul1)
; v2 = foo((b + 2) * s);
%b2 = add i32 %b, 2
%mul2 = mul i32 %b2, %s
%v2 = call i32 @foo(i32 %mul2)
; return v0 + v1 + v2;
%1 = add i32 %v0, %v1
%2 = add i32 %1, %v2
ret i32 %2
}
; v0 = foo(a * b)
; v1 = foo((a + 1) * b)
; v2 = foo(a * (b + 1))
; v3 = foo((a + 1) * (b + 1))
define i32 @slsr2(i32 %a, i32 %b) {
; CHECK-LABEL: @slsr2(
%a1 = add i32 %a, 1
%b1 = add i32 %b, 1
%mul0 = mul i32 %a, %b
; CHECK: mul i32
; CHECK-NOT: mul i32
%mul1 = mul i32 %a1, %b
%mul2 = mul i32 %a, %b1
%mul3 = mul i32 %a1, %b1
%v0 = call i32 @foo(i32 %mul0)
%v1 = call i32 @foo(i32 %mul1)
%v2 = call i32 @foo(i32 %mul2)
%v3 = call i32 @foo(i32 %mul3)
%1 = add i32 %v0, %v1
%2 = add i32 %1, %v2
%3 = add i32 %2, %v3
ret i32 %3
}
; The bump is a multiple of the stride.
;
; v0 = foo(b * s);
; v1 = foo((b + 2) * s);
; v2 = foo((b + 4) * s);
; return v0 + v1 + v2;
;
; ==>
;
; mul0 = b * s;
; v0 = foo(mul0);
; bump = s * 2;
; mul1 = mul0 + bump; // GVN ensures mul1 and mul2 use the same bump.
; v1 = foo(mul1);
; mul2 = mul1 + bump;
; v2 = foo(mul2);
; return v0 + v1 + v2;
define i32 @slsr3(i32 %b, i32 %s) {
; CHECK-LABEL: @slsr3(
%mul0 = mul i32 %b, %s
; CHECK: mul i32
%v0 = call i32 @foo(i32 %mul0)
%b1 = add i32 %b, 2
%mul1 = mul i32 %b1, %s
; CHECK: [[BUMP:%[a-zA-Z0-9]+]] = mul i32 %s, 2
; CHECK: %mul1 = add i32 %mul0, [[BUMP]]
%v1 = call i32 @foo(i32 %mul1)
%b2 = add i32 %b, 4
%mul2 = mul i32 %b2, %s
; CHECK: %mul2 = add i32 %mul1, [[BUMP]]
%v2 = call i32 @foo(i32 %mul2)
%1 = add i32 %v0, %v1
%2 = add i32 %1, %v2
ret i32 %2
}
; Do not rewrite a candidate if its potential basis does not dominate it.
; v0 = 0;
; if (cond)
; v0 = foo(a * b);
; v1 = foo((a + 1) * b);
; return v0 + v1;
define i32 @not_dominate(i1 %cond, i32 %a, i32 %b) {
; CHECK-LABEL: @not_dominate(
entry:
%a1 = add i32 %a, 1
br i1 %cond, label %then, label %merge
then:
%mul0 = mul i32 %a, %b
; CHECK: %mul0 = mul i32 %a, %b
%v0 = call i32 @foo(i32 %mul0)
br label %merge
merge:
%v0.phi = phi i32 [ 0, %entry ], [ %mul0, %then ]
%mul1 = mul i32 %a1, %b
; CHECK: %mul1 = mul i32 %a1, %b
%v1 = call i32 @foo(i32 %mul1)
%sum = add i32 %v0.phi, %v1
ret i32 %sum
}