[llvm] r354887 - [InstCombine] canonicalize more unsigned saturated add with 'not'
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Tue Feb 26 07:18:49 PST 2019
Author: spatel
Date: Tue Feb 26 07:18:49 2019
New Revision: 354887
URL: http://llvm.org/viewvc/llvm-project?rev=354887&view=rev
Log:
[InstCombine] canonicalize more unsigned saturated add with 'not'
Yet another pattern variation suggested by:
https://bugs.llvm.org/show_bug.cgi?id=14613
There are 8 more potential commuted patterns here on top of the
8 that were already handled (rL354221, rL354276, rL354393).
We have the obvious commute of the 'add' + commute of the cmp
predicate/operands (ugt/ult) + commute of the select operands:
Name: base
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
%c = icmp ult i32 %x, %y
%r = select i1 %c, i32 -1, i32 %a
=>
%c2 = icmp ult i32 %a, %y
%r = select i1 %c2, i32 -1, i32 %a
Name: ugt
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
%c = icmp ugt i32 %y, %x
%r = select i1 %c, i32 -1, i32 %a
=>
%c2 = icmp ult i32 %a, %y
%r = select i1 %c2, i32 -1, i32 %a
Name: commute select
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
%c = icmp ult i32 %y, %x
%r = select i1 %c, i32 %a, i32 -1
=>
%c2 = icmp ult i32 %a, %y
%r = select i1 %c2, i32 -1, i32 %a
Name: ugt + commute select
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
%c = icmp ugt i32 %x, %y
%r = select i1 %c, i32 %a, i32 -1
=>
%c2 = icmp ult i32 %a, %y
%r = select i1 %c2, i32 -1, i32 %a
https://rise4fun.com/Alive/den
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
llvm/trunk/test/Transforms/InstCombine/saturating-add-sub.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=354887&r1=354886&r2=354887&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Tue Feb 26 07:18:49 2019
@@ -725,6 +725,17 @@ static Value *canonicalizeSaturatedAdd(I
Value *NewCmp = Builder.CreateICmp(ICmpInst::ICMP_ULT, FVal, Y);
return Builder.CreateSelect(NewCmp, TVal, FVal);
}
+ // The 'not' op may be included in the sum but not the compare.
+ X = Cmp0;
+ Y = Cmp1;
+ if (match(FVal, m_c_Add(m_Not(m_Specific(X)), m_Specific(Y)))) {
+ // Change the comparison to use the sum (false value of the select). That is
+ // a canonical pattern match form for uadd.with.overflow:
+ // (X u< Y) ? -1 : (~X + Y) --> ((~X + Y) u< Y) ? -1 : (~X + Y)
+ // (X u< Y) ? -1 : (Y + ~X) --> ((Y + ~X) u< Y) ? -1 : (Y + ~X)
+ Value *NewCmp = Builder.CreateICmp(ICmpInst::ICMP_ULT, FVal, Y);
+ return Builder.CreateSelect(NewCmp, TVal, FVal);
+ }
return nullptr;
}
Modified: llvm/trunk/test/Transforms/InstCombine/saturating-add-sub.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/saturating-add-sub.ll?rev=354887&r1=354886&r2=354887&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/saturating-add-sub.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/saturating-add-sub.ll Tue Feb 26 07:18:49 2019
@@ -803,9 +803,9 @@ define i32 @uadd_sat_not(i32 %x, i32 %y)
; CHECK-LABEL: @uadd_sat_not(
; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
; CHECK-NEXT: [[A:%.*]] = add i32 [[NOTX]], [[Y:%.*]]
-; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[X]], [[Y]]
-; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 -1, i32 [[A]]
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]]
+; CHECK-NEXT: ret i32 [[TMP2]]
;
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
@@ -820,9 +820,9 @@ define i32 @uadd_sat_not_commute_add(i32
; CHECK-NEXT: [[Y:%.*]] = urem i32 42, [[YP:%.*]]
; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X]], -1
; CHECK-NEXT: [[A:%.*]] = add nsw i32 [[Y]], [[NOTX]]
-; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[X]], [[Y]]
-; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 -1, i32 [[A]]
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]]
+; CHECK-NEXT: ret i32 [[TMP2]]
;
%x = srem i32 42, %xp ; thwart complexity-based-canonicalization
%y = urem i32 42, %yp ; thwart complexity-based-canonicalization
@@ -837,9 +837,9 @@ define i32 @uadd_sat_not_ugt(i32 %x, i32
; CHECK-LABEL: @uadd_sat_not_ugt(
; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
; CHECK-NEXT: [[A:%.*]] = add i32 [[NOTX]], [[Y:%.*]]
-; CHECK-NEXT: [[C:%.*]] = icmp ugt i32 [[Y]], [[X]]
-; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 -1, i32 [[A]]
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]]
+; CHECK-NEXT: ret i32 [[TMP2]]
;
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
@@ -853,9 +853,9 @@ define <2 x i32> @uadd_sat_not_ugt_commu
; CHECK-NEXT: [[Y:%.*]] = sdiv <2 x i32> [[YP:%.*]], <i32 2442, i32 4242>
; CHECK-NEXT: [[NOTX:%.*]] = xor <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
; CHECK-NEXT: [[A:%.*]] = add <2 x i32> [[Y]], [[NOTX]]
-; CHECK-NEXT: [[C:%.*]] = icmp ugt <2 x i32> [[Y]], [[X]]
-; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[C]], <2 x i32> <i32 -1, i32 -1>, <2 x i32> [[A]]
-; CHECK-NEXT: ret <2 x i32> [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i32> [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select <2 x i1> [[TMP1]], <2 x i32> <i32 -1, i32 -1>, <2 x i32> [[A]]
+; CHECK-NEXT: ret <2 x i32> [[TMP2]]
;
%y = sdiv <2 x i32> %yp, <i32 2442, i32 4242> ; thwart complexity-based-canonicalization
%notx = xor <2 x i32> %x, <i32 -1, i32 -1>
@@ -869,9 +869,9 @@ define i32 @uadd_sat_not_commute_select(
; CHECK-LABEL: @uadd_sat_not_commute_select(
; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
; CHECK-NEXT: [[A:%.*]] = add i32 [[NOTX]], [[Y:%.*]]
-; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[Y]], [[X]]
-; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 [[A]], i32 -1
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]]
+; CHECK-NEXT: ret i32 [[TMP2]]
;
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
@@ -885,9 +885,9 @@ define i32 @uadd_sat_not_commute_select_
; CHECK-NEXT: [[Y:%.*]] = sdiv i32 42, [[YP:%.*]]
; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
; CHECK-NEXT: [[A:%.*]] = add i32 [[Y]], [[NOTX]]
-; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[Y]], [[X]]
-; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 [[A]], i32 -1
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]]
+; CHECK-NEXT: ret i32 [[TMP2]]
;
%y = sdiv i32 42, %yp ; thwart complexity-based-canonicalization
%notx = xor i32 %x, -1
@@ -903,9 +903,9 @@ define <2 x i32> @uadd_sat_not_commute_s
; CHECK-NEXT: [[Y:%.*]] = srem <2 x i32> <i32 12, i32 412>, [[YP:%.*]]
; CHECK-NEXT: [[NOTX:%.*]] = xor <2 x i32> [[X]], <i32 -1, i32 -1>
; CHECK-NEXT: [[A:%.*]] = add <2 x i32> [[Y]], [[NOTX]]
-; CHECK-NEXT: [[C:%.*]] = icmp ugt <2 x i32> [[X]], [[Y]]
-; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[C]], <2 x i32> [[A]], <2 x i32> <i32 -1, i32 -1>
-; CHECK-NEXT: ret <2 x i32> [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i32> [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select <2 x i1> [[TMP1]], <2 x i32> <i32 -1, i32 -1>, <2 x i32> [[A]]
+; CHECK-NEXT: ret <2 x i32> [[TMP2]]
;
%x = urem <2 x i32> <i32 42, i32 -42>, %xp ; thwart complexity-based-canonicalization
%y = srem <2 x i32> <i32 12, i32 412>, %yp ; thwart complexity-based-canonicalization
@@ -920,9 +920,9 @@ define i32 @uadd_sat_not_commute_select_
; CHECK-LABEL: @uadd_sat_not_commute_select_ugt_commute_add(
; CHECK-NEXT: [[NOTX:%.*]] = xor i32 [[X:%.*]], -1
; CHECK-NEXT: [[A:%.*]] = add i32 [[NOTX]], [[Y:%.*]]
-; CHECK-NEXT: [[C:%.*]] = icmp ugt i32 [[X]], [[Y]]
-; CHECK-NEXT: [[R:%.*]] = select i1 [[C]], i32 [[A]], i32 -1
-; CHECK-NEXT: ret i32 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[A]], [[Y]]
+; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 -1, i32 [[A]]
+; CHECK-NEXT: ret i32 [[TMP2]]
;
%notx = xor i32 %x, -1
%a = add i32 %notx, %y
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