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This is an update to a previous commit (r181216).

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The earlier change list introduced the following inst combines:
B * (uitofp i1 C) —> select C, B, 0
A * (1 - uitofp i1 C) —> select C, 0, A
select C, 0, B + select C, A, 0 —> select C, A, B

Together these 3 changes would simplify :
A * (1 - uitofp i1 C) + B * uitofp i1 C 
down to :
select C, B, A

In practice we found that the first two substitutions can have a
negative effect on performance, because they reduce opportunities to
use FMA contractions; between the two options FMAs are often the
better choice.  This change list amends the previous one to enable
just these inst combines:

select C, B, 0 + select C, 0, A —> select C, B, A
A * (1 - uitofp i1 C) + B * uitofp i1 C —> select C, B, A




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182499 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jean-Luc Duprat 2013-05-22 18:29:31 +00:00
parent e0f26bc008
commit 5e6cabd163
3 changed files with 56 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
lib/Transforms/InstCombine/InstCombineAddSub.cpp
View File

@ -1262,6 +1262,49 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
}
}
// A * (1 - uitofp i1 C) + B * (uitofp i1 C) -> select C, B, A
{
if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
Value *M1L, *M1R, *M2L, *M2R;
if (match(LHS, m_FMul(m_Value(M1L), m_Value(M1R))) &&
match(RHS, m_FMul(m_Value(M2L), m_Value(M2R)))) {
Value *A, *B, *C1, *C2;
if (!match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))))
std::swap(M1L, M1R);
if (!match(M2R, m_UIToFp(m_Value(C2))))
std::swap(M2L, M2R);
if (match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))) &&
match(M2R, m_UIToFp(m_Value(C2))) &&
C2->getType()->isIntegerTy(1) &&
C1 == C2) {
A = M1L;
B = M2L;
return SelectInst::Create(C1, B, A);
}
std::swap(M1L, M2L);
std::swap(M1R, M2R);
if (!match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))))
std::swap(M1L, M1R);
if (!match(M2R, m_UIToFp(m_Value(C2))))
std::swap(M2L, M2R);
if (match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))) &&
match(M2R, m_UIToFp(m_Value(C2))) &&
C2->getType()->isIntegerTy(1) &&
C1 == C2) {
A = M1L;
B = M2L;
return SelectInst::Create(C1, B, A);
}
}
}
}
if (I.hasUnsafeAlgebra()) {
if (Value *V = FAddCombine(Builder).simplify(&I))
return ReplaceInstUsesWith(I, V);

29
lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
View File

@ -524,35 +524,6 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
}
}
// B * (uitofp i1 C) -> select C, B, 0
if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
Value *LHS = Op0, *RHS = Op1;
Value *B, *C;
if (!match(RHS, m_UIToFp(m_Value(C))))
std::swap(LHS, RHS);
if (match(RHS, m_UIToFp(m_Value(C))) && C->getType()->isIntegerTy(1)) {
B = LHS;
Value *Zero = ConstantFP::getNegativeZero(B->getType());
return SelectInst::Create(C, B, Zero);
}
}
// A * (1 - uitofp i1 C) -> select C, 0, A
if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
Value *LHS = Op0, *RHS = Op1;
Value *A, *C;
if (!match(RHS, m_FSub(m_FPOne(), m_UIToFp(m_Value(C)))))
std::swap(LHS, RHS);
if (match(RHS, m_FSub(m_FPOne(), m_UIToFp(m_Value(C)))) &&
C->getType()->isIntegerTy(1)) {
A = LHS;
Value *Zero = ConstantFP::getNegativeZero(A->getType());
return SelectInst::Create(C, Zero, A);
}
}
if (!isa<Constant>(Op1))
std::swap(Opnd0, Opnd1);
else

40
test/Transforms/InstCombine/add4.ll
View File

@ -6,30 +6,34 @@ target triple = "i686-apple-darwin8"
define float @test1(float %A, float %B, i1 %C) {
EntryBlock:
;; A*(1 - uitofp i1 C) -> select C, 0, A
;; select C, 0, B + select C, A, 0 -> select C, A, B
%cf = uitofp i1 %C to float
%mc = fsub float 1.000000e+00, %cf
%p1 = fmul fast float %A, %mc
ret float %p1
%s1 = select i1 %C, float 0.000000e+00, float %B
%s2 = select i1 %C, float %A, float 0.000000e+00
%sum = fadd fast float %s1, %s2
ret float %sum
; CHECK: @test1
; CHECK: select i1 %C, float -0.000000e+00, float %A
; CHECK: select i1 %C, float %A, float %B
}
define float @test2(float %A, float %B, i1 %C) {
EntryBlock:
;; B*(uitofp i1 C) -> select C, B, 0
;; B*(uitofp i1 C) + A*(1 - uitofp i1 C) -> select C, A, B
%cf = uitofp i1 %C to float
%mc = fsub fast float 1.000000e+00, %cf
%p1 = fmul fast float %A, %mc
%p2 = fmul fast float %B, %cf
ret float %p2
%s1 = fadd fast float %p2, %p1
ret float %s1
; CHECK: @test2
; CHECK: select i1 %C, float %B, float -0.000000e+00
; CHECK: select i1 %C, float %B, float %A
}
define float @test3(float %A, float %B, i1 %C) {
EntryBlock:
;; A*(1 - uitofp i1 C) + B*(uitofp i1 C) -> select C, A, B
%cf = uitofp i1 %C to float
%mc = fsub float 1.000000e+00, %cf
%mc = fsub fast float 1.000000e+00, %cf
%p1 = fmul fast float %A, %mc
%p2 = fmul fast float %B, %cf
%s1 = fadd fast float %p1, %p2
@ -38,21 +42,3 @@ EntryBlock:
; CHECK: select i1 %C, float %B, float %A
}
; PR15952
define float @test4(float %A, float %B, i32 %C) {
%cf = uitofp i32 %C to float
%mc = fsub float 1.000000e+00, %cf
%p1 = fmul fast float %A, %mc
ret float %p1
; CHECK: @test4
; CHECK: uitofp
}
define float @test5(float %A, float %B, i32 %C) {
%cf = uitofp i32 %C to float
%p2 = fmul fast float %B, %cf
ret float %p2
; CHECK: @test5
; CHECK: uitofp
}