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;=========================== begin_copyright_notice ============================
;
; Copyright (C) 2025 Intel Corporation
;
; SPDX-License-Identifier: MIT
;
;============================ end_copyright_notice =============================
; RUN: igc_opt -wave-ballot-cse -S %s | FileCheck %s
; Test that CSE does NOT work across basic blocks (due to convergent nature)
define i32 @test_no_cross_block_cse(i1 %cond) {
; CHECK-LABEL: @test_no_cross_block_cse
; CHECK-NEXT: %mask1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
; CHECK-NEXT: br i1 %cond, label %then, label %else
; CHECK: then:
; CHECK-NEXT: %mask2 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
; CHECK-NEXT: %result_then = add i32 %mask1, %mask2
; CHECK-NEXT: br label %merge
; CHECK: else:
; CHECK-NEXT: %mask3 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
; CHECK-NEXT: %result_else = add i32 %mask1, %mask3
; CHECK-NEXT: br label %merge
; CHECK: merge:
; CHECK-NEXT: %result = phi i32 [ %result_then, %then ], [ %result_else, %else ]
; CHECK-NEXT: ret i32 %result
;
%mask1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
br i1 %cond, label %then, label %else
then:
%mask2 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
%result_then = add i32 %mask1, %mask2
br label %merge
else:
%mask3 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
%result_else = add i32 %mask1, %mask3
br label %merge
merge:
%result = phi i32 [ %result_then, %then ], [ %result_else, %else ]
ret i32 %result
}
; Test within-block CSE works in multiple blocks
define i32 @test_within_block_cse_multiple_blocks(i1 %cond) {
; CHECK-LABEL: @test_within_block_cse_multiple_blocks
; CHECK-NEXT: %mask1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
; CHECK-NEXT: %entry_work = add i32 %mask1, %mask1
; CHECK-NEXT: br i1 %cond, label %then, label %else
; CHECK: then:
; CHECK-NEXT: %mask_then = call i32 @llvm.genx.GenISA.WaveBallot(i1 false, i32 1)
; CHECK-NEXT: %result_then = add i32 %mask_then, %mask_then
; CHECK-NEXT: br label %merge
; CHECK: else:
; CHECK-NEXT: %mask_else = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 2)
; CHECK-NEXT: %result_else = add i32 %mask_else, %mask_else
; CHECK-NEXT: br label %merge
; CHECK: merge:
; CHECK-NEXT: %result = phi i32 [ %result_then, %then ], [ %result_else, %else ]
; CHECK-NEXT: %final = add i32 %result, %entry_work
; CHECK-NEXT: ret i32 %final
;
%mask1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
%mask1_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
%entry_work = add i32 %mask1, %mask1_dup
br i1 %cond, label %then, label %else
then:
%mask_then = call i32 @llvm.genx.GenISA.WaveBallot(i1 false, i32 1)
%mask_then_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 false, i32 1)
%result_then = add i32 %mask_then, %mask_then_dup
br label %merge
else:
%mask_else = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 2)
%mask_else_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 2)
%result_else = add i32 %mask_else, %mask_else_dup
br label %merge
merge:
%result = phi i32 [ %result_then, %then ], [ %result_else, %else ]
%final = add i32 %result, %entry_work
ret i32 %final
}
; Test complex control flow
define i32 @test_complex_control_flow(i1 %cond1, i1 %cond2) {
; CHECK-LABEL: @test_complex_control_flow
; CHECK-NEXT: %mask1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
; CHECK-NEXT: %entry_result = add i32 %mask1, %mask1
; CHECK-NEXT: br i1 %cond1, label %branch1, label %branch2
; CHECK: branch1:
; CHECK-NEXT: br i1 %cond2, label %nested1, label %nested2
; CHECK: nested1:
; CHECK-NEXT: %mask_n1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 false, i32 1)
; CHECK-NEXT: %n1_result = add i32 %mask_n1, %mask_n1
; CHECK-NEXT: br label %merge
; CHECK: nested2:
; CHECK-NEXT: %mask_n2 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 1)
; CHECK-NEXT: %n2_result = add i32 %mask_n2, %mask_n2
; CHECK-NEXT: br label %merge
; CHECK: branch2:
; CHECK-NEXT: %mask_b2 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 2)
; CHECK-NEXT: %b2_result = add i32 %mask_b2, %mask_b2
; CHECK-NEXT: br label %merge
; CHECK: merge:
; CHECK-NEXT: %result = phi i32 [ %n1_result, %nested1 ], [ %n2_result, %nested2 ], [ %b2_result, %branch2 ]
; CHECK-NEXT: %final = add i32 %result, %entry_result
; CHECK-NEXT: ret i32 %final
;
%mask1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
%mask1_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 0)
%entry_result = add i32 %mask1, %mask1_dup
br i1 %cond1, label %branch1, label %branch2
branch1:
br i1 %cond2, label %nested1, label %nested2
nested1:
%mask_n1 = call i32 @llvm.genx.GenISA.WaveBallot(i1 false, i32 1)
%mask_n1_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 false, i32 1)
%n1_result = add i32 %mask_n1, %mask_n1_dup
br label %merge
nested2:
%mask_n2 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 1)
%mask_n2_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 1)
%n2_result = add i32 %mask_n2, %mask_n2_dup
br label %merge
branch2:
%mask_b2 = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 2)
%mask_b2_dup = call i32 @llvm.genx.GenISA.WaveBallot(i1 true, i32 2)
%b2_result = add i32 %mask_b2, %mask_b2_dup
br label %merge
merge:
%result = phi i32 [ %n1_result, %nested1 ], [ %n2_result, %nested2 ], [ %b2_result, %branch2 ]
%final = add i32 %result, %entry_result
ret i32 %final
}
declare i32 @llvm.genx.GenISA.WaveBallot(i1, i32)
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