[llvm] f6f1fd4 - Revert "[InstCombine] allow more folds more multi-use selects"
Michał Górny via llvm-commits
llvm-commits at lists.llvm.org
Sat Nov 12 23:33:54 PST 2022
Author: Michał Górny
Date: 2022-11-13T07:27:01+01:00
New Revision: f6f1fd443f48f417de9dfe23353055f1b20d87ef
URL: https://github.com/llvm/llvm-project/commit/f6f1fd443f48f417de9dfe23353055f1b20d87ef
DIFF: https://github.com/llvm/llvm-project/commit/f6f1fd443f48f417de9dfe23353055f1b20d87ef.diff
LOG: Revert "[InstCombine] allow more folds more multi-use selects"
This reverts commit 681a6a3990226c667fb648952731d2753df2716d.
It broke sanitizer tests (as seen on buildbots), see:
https://reviews.llvm.org/rG681a6a399022#1143137
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
llvm/test/Transforms/InstCombine/binop-select.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index f6cd9260c1499..61bac17811326 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -919,24 +919,18 @@ Value *InstCombinerImpl::SimplifySelectsFeedingBinaryOp(BinaryOperator &I,
else if (True && !False)
False = Builder.CreateBinOp(Opcode, C, F);
}
- } else if (LHSIsSelect) {
+ } else if (LHSIsSelect && LHS->hasOneUse()) {
// (A ? B : C) op Y -> A ? (B op Y) : (C op Y)
Cond = A;
True = simplifyBinOp(Opcode, B, RHS, FMF, Q);
False = simplifyBinOp(Opcode, C, RHS, FMF, Q);
- if (!LHS->hasOneUse() &&
- (!True || !False || !isa<Constant>(True) || !isa<Constant>(False)))
- return nullptr;
if (Value *NewSel = foldAddNegate(B, C, RHS))
return NewSel;
- } else if (RHSIsSelect) {
+ } else if (RHSIsSelect && RHS->hasOneUse()) {
// X op (D ? E : F) -> D ? (X op E) : (X op F)
Cond = D;
True = simplifyBinOp(Opcode, LHS, E, FMF, Q);
False = simplifyBinOp(Opcode, LHS, F, FMF, Q);
- if (!RHS->hasOneUse() &&
- (!True || !False || !isa<Constant>(True) || !isa<Constant>(False)))
- return nullptr;
if (Value *NewSel = foldAddNegate(E, F, LHS))
return NewSel;
}
diff --git a/llvm/test/Transforms/InstCombine/binop-select.ll b/llvm/test/Transforms/InstCombine/binop-select.ll
index cce1206f1b90e..90f41a29aed57 100644
--- a/llvm/test/Transforms/InstCombine/binop-select.ll
+++ b/llvm/test/Transforms/InstCombine/binop-select.ll
@@ -188,13 +188,11 @@ define i32 @and_sel_op0(i1 %b) {
ret i32 %r
}
-; extra use is ok
-
define i32 @and_sel_op0_use(i1 %b) {
; CHECK-LABEL: @and_sel_op0_use(
; CHECK-NEXT: [[S:%.*]] = select i1 [[B:%.*]], i32 25, i32 0
; CHECK-NEXT: call void @use(i32 [[S]])
-; CHECK-NEXT: [[R:%.*]] = zext i1 [[B]] to i32
+; CHECK-NEXT: [[R:%.*]] = and i32 [[S]], 1
; CHECK-NEXT: ret i32 [[R]]
;
%s = select i1 %b, i32 25, i32 0
@@ -214,14 +212,12 @@ define i32 @mul_sel_op0(i1 %b, i32 %x) {
ret i32 %r
}
-; extra use is ok
-
define i32 @mul_sel_op0_use(i1 %b, i32 %x) {
; CHECK-LABEL: @mul_sel_op0_use(
; CHECK-NEXT: [[D:%.*]] = udiv exact i32 42, [[X:%.*]]
; CHECK-NEXT: [[S:%.*]] = select i1 [[B:%.*]], i32 0, i32 [[D]]
; CHECK-NEXT: call void @use(i32 [[S]])
-; CHECK-NEXT: [[R:%.*]] = select i1 [[B]], i32 0, i32 42
+; CHECK-NEXT: [[R:%.*]] = mul i32 [[S]], [[X]]
; CHECK-NEXT: ret i32 [[R]]
;
%d = udiv exact i32 42, %x
@@ -242,14 +238,11 @@ define i32 @sub_sel_op1(i1 %b) {
ret i32 %r
}
-; extra use is ok (extra instruction caused by select canonicalization to zext (!b))
-
define i32 @sub_sel_op1_use(i1 %b) {
; CHECK-LABEL: @sub_sel_op1_use(
; CHECK-NEXT: [[S:%.*]] = select i1 [[B:%.*]], i32 42, i32 41
; CHECK-NEXT: call void @use(i32 [[S]])
-; CHECK-NEXT: [[NOT_B:%.*]] = xor i1 [[B]], true
-; CHECK-NEXT: [[R:%.*]] = zext i1 [[NOT_B]] to i32
+; CHECK-NEXT: [[R:%.*]] = sub nsw i32 42, [[S]]
; CHECK-NEXT: ret i32 [[R]]
;
%s = select i1 %b, i32 42, i32 41
@@ -268,13 +261,11 @@ define float @fadd_sel_op0(i1 %b, float %x) {
ret float %r
}
-; extra use is ok
-
define float @fadd_sel_op0_use(i1 %b, float %x) {
; CHECK-LABEL: @fadd_sel_op0_use(
; CHECK-NEXT: [[S:%.*]] = select i1 [[B:%.*]], float 0xFFF0000000000000, float 0x7FF0000000000000
; CHECK-NEXT: call void @use_f32(float [[S]])
-; CHECK-NEXT: [[R:%.*]] = select nnan i1 [[B]], float 0xFFF0000000000000, float 0x7FF0000000000000
+; CHECK-NEXT: [[R:%.*]] = fadd nnan float [[S]], [[X:%.*]]
; CHECK-NEXT: ret float [[R]]
;
%s = select i1 %b, float 0xFFF0000000000000, float 0x7FF0000000000000
@@ -293,13 +284,13 @@ define <2 x half> @fmul_sel_op1(i1 %b, <2 x half> %p) {
ret <2 x half> %r
}
-; extra use is ok - poison allows simplifying
-
define <2 x half> @fmul_sel_op1_use(i1 %b, <2 x half> %p) {
; CHECK-LABEL: @fmul_sel_op1_use(
+; CHECK-NEXT: [[X:%.*]] = fadd <2 x half> [[P:%.*]], <half 0xH3C00, half 0xH4000>
; CHECK-NEXT: [[S:%.*]] = select i1 [[B:%.*]], <2 x half> zeroinitializer, <2 x half> <half 0xHFFFF, half 0xHFFFF>
; CHECK-NEXT: call void @use_v2f16(<2 x half> [[S]])
-; CHECK-NEXT: ret <2 x half> zeroinitializer
+; CHECK-NEXT: [[R:%.*]] = fmul nnan nsz <2 x half> [[X]], [[S]]
+; CHECK-NEXT: ret <2 x half> [[R]]
;
%x = fadd <2 x half> %p, <half 1.0, half 2.0> ; thwart complexity-based canonicalization
%s = select i1 %b, <2 x half> zeroinitializer, <2 x half> <half 0xHffff, half 0xHffff>
@@ -318,8 +309,6 @@ define i32 @ashr_sel_op1(i1 %b) {
ret i32 %r
}
-; TODO: SimplifySelectsFeedingBinaryOp() is not called for shifts; previous test reduced some other way.
-
define i32 @ashr_sel_op1_use(i1 %b) {
; CHECK-LABEL: @ashr_sel_op1_use(
; CHECK-NEXT: [[S:%.*]] = select i1 [[B:%.*]], i32 2, i32 0
More information about the llvm-commits
mailing list