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llvm-project/llvm/test/Transforms/InstCombine/phi-select-constant.ll

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Don't use isNullValue to evaluate ConstantExpr ConstantExpr can evaluate to false even when isNullValue gives false. Fixes PR18143. llvm-svn: 196611
2013-12-07 05:48:36 +08:00
; RUN: opt < %s -S -instcombine | FileCheck %s
@A = extern_weak global i32, align 4
@B = extern_weak global i32, align 4
define i32 @foo(i1 %which) {
entry:
br i1 %which, label %final, label %delay
delay:
br label %final
[InstCombine] Avoid incorrect folding of select into phi nodes when incoming element is a vector type Summary: We are incorrectly folding selects into phi nodes when the incoming value of a phi node is a constant vector. This optimization is done in `FoldOpIntoPhi` when the select condition is a phi node with constant incoming values. Without the fix, we are miscompiling (i.e. incorrectly folding the select into the phi node) when the vector contains non-zero elements. This patch fixes the miscompile and we will correctly fold based on the select vector operand (see added test cases). Reviewers: majnemer, sanjoy, spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D31189 llvm-svn: 298845
2017-03-27 21:52:51 +08:00
; CHECK-LABEL: @foo
Don't use isNullValue to evaluate ConstantExpr ConstantExpr can evaluate to false even when isNullValue gives false. Fixes PR18143. llvm-svn: 196611
2013-12-07 05:48:36 +08:00
; CHECK-LABEL: final:
; CHECK: phi i32 [ 1, %entry ], [ select (i1 icmp eq (i32* @A, i32* @B), i32 2, i32 1), %delay ]
final:
%use2 = phi i1 [ false, %entry ], [ icmp eq (i32* @A, i32* @B), %delay ]
%value = select i1 %use2, i32 2, i32 1
ret i32 %value
}
[InstCombine] Avoid incorrect folding of select into phi nodes when incoming element is a vector type Summary: We are incorrectly folding selects into phi nodes when the incoming value of a phi node is a constant vector. This optimization is done in `FoldOpIntoPhi` when the select condition is a phi node with constant incoming values. Without the fix, we are miscompiling (i.e. incorrectly folding the select into the phi node) when the vector contains non-zero elements. This patch fixes the miscompile and we will correctly fold based on the select vector operand (see added test cases). Reviewers: majnemer, sanjoy, spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D31189 llvm-svn: 298845
2017-03-27 21:52:51 +08:00
; test folding of select into phi for vectors.
define <4 x i64> @vec1(i1 %which) {
entry:
br i1 %which, label %final, label %delay
delay:
br label %final
final:
; CHECK-LABEL: @vec1
; CHECK-LABEL: final:
; CHECK: %phinode = phi <4 x i64> [ zeroinitializer, %entry ], [ <i64 0, i64 0, i64 126, i64 127>, %delay ]
; CHECK-NOT: select
; CHECK: ret <4 x i64> %phinode
%phinode = phi <4 x i1> [ <i1 true, i1 true, i1 true, i1 true>, %entry ], [ <i1 true, i1 true, i1 false, i1 false>, %delay ]
%sel = select <4 x i1> %phinode, <4 x i64> zeroinitializer, <4 x i64> <i64 124, i64 125, i64 126, i64 127>
ret <4 x i64> %sel
}
define <4 x i64> @vec2(i1 %which) {
entry:
br i1 %which, label %final, label %delay
delay:
br label %final
final:
; CHECK-LABEL: @vec2
; CHECK-LABEL: final:
; CHECK: %phinode = phi <4 x i64> [ <i64 124, i64 125, i64 126, i64 127>, %entry ], [ <i64 0, i64 125, i64 0, i64 127>, %delay ]
; CHECK-NOT: select
; CHECK: ret <4 x i64> %phinode
%phinode = phi <4 x i1> [ <i1 false, i1 false, i1 false, i1 false>, %entry ], [ <i1 true, i1 false, i1 true, i1 false>, %delay ]
%sel = select <4 x i1> %phinode, <4 x i64> zeroinitializer, <4 x i64> <i64 124, i64 125, i64 126, i64 127>
ret <4 x i64> %sel
}
[InstCombine] Set correct insertion point for selects generated while folding phis Summary: When we fold vector constants that are operands of phi's that feed into select, we need to set the correct insertion point for the *new* selects that get generated. The correct insertion point is the incoming block for the phi. Such cases can occur with patch r298845, which fixed folding of vector constants, but the new selects could be inserted incorrectly (as the added test case shows). Reviewers: majnemer, spatel, sanjoy Reviewed by: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34162 llvm-svn: 305591
2017-06-17 05:08:37 +08:00
; Test PR33364
; Insert the generated select into the same block as the incoming phi value.
; phi has constant vectors along with a single non-constant vector as operands.
define <2 x i8> @vec3(i1 %cond1, i1 %cond2, <2 x i1> %x, <2 x i8> %y, <2 x i8> %z) {
; CHECK-LABEL: @vec3
Fix some misc. -enable-var-scope violations llvm-svn: 318006
2017-11-13 09:47:52 +08:00
; CHECK: entry:
[InstCombine] Set correct insertion point for selects generated while folding phis Summary: When we fold vector constants that are operands of phi's that feed into select, we need to set the correct insertion point for the *new* selects that get generated. The correct insertion point is the incoming block for the phi. Such cases can occur with patch r298845, which fixed folding of vector constants, but the new selects could be inserted incorrectly (as the added test case shows). Reviewers: majnemer, spatel, sanjoy Reviewed by: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34162 llvm-svn: 305591
2017-06-17 05:08:37 +08:00
; CHECK-NEXT: [[PHITMP1:%.*]] = shufflevector <2 x i8> %y, <2 x i8> %z, <2 x i32> <i32 2, i32 1>
entry:
br i1 %cond1, label %if1, label %else
Fix some misc. -enable-var-scope violations llvm-svn: 318006
2017-11-13 09:47:52 +08:00
; CHECK: if1:
[InstCombine] Set correct insertion point for selects generated while folding phis Summary: When we fold vector constants that are operands of phi's that feed into select, we need to set the correct insertion point for the *new* selects that get generated. The correct insertion point is the incoming block for the phi. Such cases can occur with patch r298845, which fixed folding of vector constants, but the new selects could be inserted incorrectly (as the added test case shows). Reviewers: majnemer, spatel, sanjoy Reviewed by: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34162 llvm-svn: 305591
2017-06-17 05:08:37 +08:00
; CHECK-NEXT: [[PHITMP2:%.*]] = shufflevector <2 x i8> %y, <2 x i8> %z, <2 x i32> <i32 0, i32 3>
if1:
br i1 %cond2, label %if2, label %else
Fix some misc. -enable-var-scope violations llvm-svn: 318006
2017-11-13 09:47:52 +08:00
; CHECK: if2:
[InstCombine] Set correct insertion point for selects generated while folding phis Summary: When we fold vector constants that are operands of phi's that feed into select, we need to set the correct insertion point for the *new* selects that get generated. The correct insertion point is the incoming block for the phi. Such cases can occur with patch r298845, which fixed folding of vector constants, but the new selects could be inserted incorrectly (as the added test case shows). Reviewers: majnemer, spatel, sanjoy Reviewed by: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34162 llvm-svn: 305591
2017-06-17 05:08:37 +08:00
; CHECK-NEXT: [[PHITMP3:%.*]] = select <2 x i1> %x, <2 x i8> %y, <2 x i8> %z
if2:
br label %else
Fix some misc. -enable-var-scope violations llvm-svn: 318006
2017-11-13 09:47:52 +08:00
; CHECK: else:
[InstCombine] Set correct insertion point for selects generated while folding phis Summary: When we fold vector constants that are operands of phi's that feed into select, we need to set the correct insertion point for the *new* selects that get generated. The correct insertion point is the incoming block for the phi. Such cases can occur with patch r298845, which fixed folding of vector constants, but the new selects could be inserted incorrectly (as the added test case shows). Reviewers: majnemer, spatel, sanjoy Reviewed by: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34162 llvm-svn: 305591
2017-06-17 05:08:37 +08:00
; CHECK-NEXT: [[PHITMP4:%.*]] = phi <2 x i8> [ [[PHITMP3]], %if2 ], [ [[PHITMP1]], %entry ], [ [[PHITMP2]], %if1 ]
; CHECK-NEXT: ret <2 x i8> [[PHITMP4]]
else:
%phi = phi <2 x i1> [ %x, %if2 ], [ <i1 0, i1 1>, %entry ], [ <i1 1, i1 0>, %if1 ]
%sel = select <2 x i1> %phi, <2 x i8> %y, <2 x i8> %z
ret <2 x i8> %sel
}