[llvm] [LoopInterchange] Drop nuw/nsw flags from reduction ops when interchanging (PR #148612)
Sjoerd Meijer via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 15 02:05:33 PDT 2025
================
@@ -0,0 +1,731 @@
+; RUN: opt < %s -passes=loop-interchange -cache-line-size=64 -pass-remarks-output=%t -disable-output \
+; RUN: -verify-dom-info -verify-loop-info -verify-loop-lcssa
+; RUN: FileCheck -input-file=%t %s
+
+; Check that exchanging the loops is legal for the bitwise-or reduction.
+;
+; int b_or = 0;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; b_or |= A[j][i];
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_or
+define void @reduction_or(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %or.i = phi i32 [ 0, %entry ], [ %or.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %or.j = phi i32 [ %or.i, %for.i.header ], [ %or.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %or.j.next = or i32 %or.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %or.i.lcssa = phi i32 [ %or.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the bitwise-and reduction.
+;
+; int b_and = -1;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; b_and &= A[j][i];
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_and
+define void @reduction_and(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %and.i = phi i32 [ -1, %entry ], [ %and.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %and.j = phi i32 [ %and.i, %for.i.header ], [ %and.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %and.j.next = and i32 %and.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %and.i.lcssa = phi i32 [ %and.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the bitwise-xor reduction.
+;
+; int b_xor = 0;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; b_xor ^= A[j][i];
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_xor
+define void @reduction_xor(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %xor.i = phi i32 [ 0, %entry ], [ %xor.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %xor.j = phi i32 [ %xor.i, %for.i.header ], [ %xor.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %xor.j.next = xor i32 %xor.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %xor.i.lcssa = phi i32 [ %xor.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the signed-minimum reduction.
+;
+; int smin = init;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; smin = (A[j][i] < smin) ? A[j][i] : smin;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_smin
+define void @reduction_smin(ptr %A, i32 %init) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %smin.i = phi i32 [ %init, %entry ], [ %smin.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %smin.j = phi i32 [ %smin.i, %for.i.header ], [ %smin.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %cmp = icmp slt i32 %a, %smin.j
+ %smin.j.next = select i1 %cmp, i32 %a, i32 %smin.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %smin.i.lcssa = phi i32 [ %smin.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the signed-maximum reduction.
+;
+; int smax = init;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; smax = (A[j][i] > smax) ? A[j][i] : smax;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_smax
+define void @reduction_smax(ptr %A, i32 %init) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %smax.i = phi i32 [ %init, %entry ], [ %smax.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %smax.j = phi i32 [ %smax.i, %for.i.header ], [ %smax.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %cmp = icmp sgt i32 %a, %smax.j
+ %smax.j.next = select i1 %cmp, i32 %a, i32 %smax.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %smax.i.lcssa = phi i32 [ %smax.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the unsigned-minimum reduction.
+;
+; unsigned umin = init;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; umin = (A[j][i] < umin) ? A[j][i] : umin;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_umin
+define void @reduction_umin(ptr %A, i32 %init) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %umin.i = phi i32 [ %init, %entry ], [ %umin.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %umin.j = phi i32 [ %umin.i, %for.i.header ], [ %umin.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %cmp = icmp ult i32 %a, %umin.j
+ %umin.j.next = select i1 %cmp, i32 %a, i32 %umin.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %umin.i.lcssa = phi i32 [ %umin.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the unsigned-maximum reduction.
+;
+; unsigned umax = 0;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; smax = (A[j][i] > smax) ? A[j][i] : smax;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_umax
+define void @reduction_umax(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %umax.i = phi i32 [ 0, %entry ], [ %umax.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %umax.j = phi i32 [ %umax.i, %for.i.header ], [ %umax.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %cmp = icmp ugt i32 %a, %umax.j
+ %umax.j.next = select i1 %cmp, i32 %a, i32 %umax.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %umax.i.lcssa = phi i32 [ %umax.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the any-of reduction.
+;
+; int any_of = 0;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; any_of = (A[j][i] == 42) ? 1 : any_of;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_anyof
+define void @reduction_anyof(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %anyof.i = phi i32 [ 0, %entry ], [ %anyof.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %anyof.j = phi i32 [ %anyof.i, %for.i.header ], [ %anyof.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load i32, ptr %idx, align 4
+ %cmp = icmp eq i32 %a, 42
+ %anyof.j.next = select i1 %cmp, i32 1, i32 %anyof.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %anyof.i.lcssa = phi i32 [ %anyof.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that the loops aren't exchanged if there is a reduction of
+; non-reassociative floating-point addition.
+;
+; float sum = 0;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; sum += A[j][i];
+
+; CHECK: --- !Missed
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: UnsupportedPHIOuter
+; CHECK-NEXT: Function: reduction_fadd
+define void @reduction_fadd(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %sum.i = phi float [ 0.0, %entry ], [ %sum.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %sum.j = phi float [ %sum.i, %for.i.header ], [ %sum.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %sum.j.next = fadd float %sum.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %sum.i.lcssa = phi float [ %sum.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that the interchange is legal if the floation-point addition is marked
+; as reassoc.
+;
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_reassoc_fadd
+define void @reduction_reassoc_fadd(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %sum.i = phi float [ 0.0, %entry ], [ %sum.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %sum.j = phi float [ %sum.i, %for.i.header ], [ %sum.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %sum.j.next = fadd reassoc float %sum.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %sum.i.lcssa = phi float [ %sum.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that the loops aren't exchanged if there is a reduction of
+; non-reassociative floating-point multiplication.
+;
+; float prod = 1;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; prod *= A[j][i];
+
+; CHECK: --- !Missed
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: UnsupportedPHIOuter
+; CHECK-NEXT: Function: reduction_fmul
+define void @reduction_fmul(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %prod.i = phi float [ 1.0, %entry ], [ %prod.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %prod.j = phi float [ %prod.i, %for.i.header ], [ %prod.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %prod.j.next = fmul float %prod.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %prod.i.lcssa = phi float [ %prod.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that the interchange is legal if the floation-point multiplication is
+; marked as reassoc.
+;
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_reassoc_fmul
+define void @reduction_reassoc_fmul(ptr %A) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %prod.i = phi float [ 1.0, %entry ], [ %prod.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %prod.j = phi float [ %prod.i, %for.i.header ], [ %prod.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %prod.j.next = fmul reassoc float %prod.j, %a
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %prod.i.lcssa = phi float [ %prod.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that the loops aren't exchanged if there is a reduction of
+; non-reassociative floating-point fmuladd.
+;
+; float fmuladd = 0;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; fmuladd += A[j][i] * B[j][i];
+
+; CHECK: --- !Missed
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: UnsupportedPHIOuter
+; CHECK-NEXT: Function: reduction_fmuladd
+define void @reduction_fmuladd(ptr %A, ptr %B) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %fmuladd.i = phi float [ 1.0, %entry ], [ %fmuladd.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %fmuladd.j = phi float [ %fmuladd.i, %for.i.header ], [ %fmuladd.j.next, %for.j ]
+ %idx.a = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %idx.b = getelementptr inbounds [2 x [2 x i32]], ptr %B, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx.a, align 4
+ %b = load float, ptr %idx.b, align 4
+ %fmuladd.j.next = call float @llvm.fmuladd.f32(float %a, float %b, float %fmuladd.j)
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %fmuladd.i.lcssa = phi float [ %fmuladd.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that the interchange is legal if the floation-point fmuladd is marked
+; as reassoc.
+;
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_reassoc_fmuladd
+define void @reduction_reassoc_fmuladd(ptr %A, ptr %B) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %fmuladd.i = phi float [ 1.0, %entry ], [ %fmuladd.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %fmuladd.j = phi float [ %fmuladd.i, %for.i.header ], [ %fmuladd.j.next, %for.j ]
+ %idx.a = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %idx.b = getelementptr inbounds [2 x [2 x i32]], ptr %B, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx.a, align 4
+ %b = load float, ptr %idx.b, align 4
+ %fmuladd.j.next = call reassoc float @llvm.fmuladd.f32(float %a, float %b, float %fmuladd.j)
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %fmuladd.i.lcssa = phi float [ %fmuladd.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that exchanging the loops is legal for the reassociative floating-point
+; minimum.
+;
+; float fmin = init;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; fmin = (A[j][i] < fmin) ? A[j][i] : fmin;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_fmin
+define void @reduction_fmin(ptr %A, float %init) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %fmin.i = phi float [ %init, %entry ], [ %fmin.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %fmin.j = phi float [ %fmin.i, %for.i.header ], [ %fmin.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %cmp = fcmp nnan nsz olt float %a, %fmin.j
+ %fmin.j.next = select nnan nsz i1 %cmp, float %a, float %fmin.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %fmin.i.lcssa = phi float [ %fmin.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+
+; Check that exchanging the loops is legal for the floation-point
+; llvm.minimumnum.
+;
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_fmininumnum
+define void @reduction_fmininumnum(ptr %A, float %init) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %fmin.i = phi float [ %init, %entry ], [ %fmin.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %fmin.j = phi float [ %fmin.i, %for.i.header ], [ %fmin.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %fmin.j.next = call float @llvm.minimumnum.f32(float %a, float %fmin.j)
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %fmin.i.lcssa = phi float [ %fmin.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that exchanging the loops is legal for the reassociative floating-point
+; maximum.
+;
+; float fmax = init;
+; for (int i = 0; i < 2; i++)
+; for (int j = 0; j < 2; j++)
+; fmax = (A[j][i] > fmax) ? A[j][i] : fmax;
+
+; CHECK: --- !Pass
+; CHECK-NEXT: Pass: loop-interchange
+; CHECK-NEXT: Name: Interchanged
+; CHECK-NEXT: Function: reduction_fmax
+define void @reduction_fmax(ptr %A, float %init) {
+entry:
+ br label %for.i.header
+
+for.i.header:
+ %i = phi i32 [ 0, %entry ], [ %i.inc, %for.i.latch ]
+ %fmax.i = phi float [ %init, %entry ], [ %fmax.i.lcssa, %for.i.latch ]
+ br label %for.j
+
+for.j:
+ %j = phi i32 [ 0, %for.i.header ], [ %j.inc, %for.j ]
+ %fmax.j = phi float [ %fmax.i, %for.i.header ], [ %fmax.j.next, %for.j ]
+ %idx = getelementptr inbounds [2 x [2 x i32]], ptr %A, i32 0, i32 %j, i32 %i
+ %a = load float, ptr %idx, align 4
+ %cmp = fcmp nnan nsz ogt float %a, %fmax.j
+ %fmax.j.next = select nnan nsz i1 %cmp, float %a, float %fmax.j
+ %j.inc = add i32 %j, 1
+ %cmp.j = icmp slt i32 %j.inc, 2
+ br i1 %cmp.j, label %for.j, label %for.i.latch
+
+for.i.latch:
+ %fmax.i.lcssa = phi float [ %fmax.j.next, %for.j ]
+ %i.inc = add i32 %i, 1
+ %cmp.i = icmp slt i32 %i.inc, 2
+ br i1 %cmp.i, label %for.i.header, label %exit
+
+exit:
+ ret void
+}
+
+; Check that exchanging the loops is legal for the floation-point
----------------
sjoerdmeijer wrote:
Same
https://github.com/llvm/llvm-project/pull/148612
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