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[PATCH 2/5] [ifcvt] optimize x=c ? (y shift_op z):y by RISC-V Zicond like insns

Browse source 
op=[ASHIFT, ASHIFTRT, LSHIFTRT, ROTATE, ROTATERT]

Conditional op, if zero
rd = (rc == 0) ? (rs1 op rs2) : rs1
-->
czero.nez rd, rs2, rc
op rd, rs1, rd

Conditional op, if non-zero
rd = (rc != 0) ? (rs1 op rs2) : rs1
-->
czero.eqz rd, rs2, rc
op rd, rs1, rd

gcc/ChangeLog:

	* ifcvt.cc (noce_cond_zero_binary_op_supported): Add support for shift
	like op.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/zicond_ifcvt_opt.c: Add tests for shift like op.

Co-authored-by: Xiao Zeng<zengxiao@eswincomputing.com>
This commit is contained in:
Fei Gao 2023-12-10 13:39:30 -07:00 • committed by Jeff Law
parent b3aed45963
commit 5a4faf9155
2 changed files with 56 additions and 1 deletions
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4
gcc/ifcvt.cc
View file

@ -2920,7 +2920,9 @@ noce_cond_zero_binary_op_supported (rtx op)
{
enum rtx_code opcode = GET_CODE (op);
if (opcode == PLUS || opcode == MINUS || opcode == IOR || opcode == XOR)
if (opcode == PLUS || opcode == MINUS || opcode == IOR || opcode == XOR
|| opcode == ASHIFT || opcode == ASHIFTRT || opcode == LSHIFTRT
|| opcode == ROTATE || opcode == ROTATERT)
return true;
return false;

53
gcc/testsuite/gcc.target/riscv/zicond_ifcvt_opt.c
View file

@ -562,5 +562,58 @@ test_XOR_eqz_x_2_reverse_bin_oprands (long x, long z, long c)
return x;
}
long
test_ShiftLeft_eqz (long x, long y, long z, long c)
{
if (c)
x = y << z;
else
x = y;
return x;
}
long
test_ShiftR_eqz (long x, long y, long z, long c)
{
if (c)
x = y >> z;
else
x = y;
return x;
}
unsigned long
test_ShiftR_logical_eqz (unsigned long x, unsigned long y, unsigned long z,
unsigned long c)
{
if (c)
x = y >> z;
else
x = y;
return x;
}
unsigned long
test_RotateL_eqz (unsigned long x, unsigned long y, unsigned long z,
unsigned long c)
{
if (c)
x = (y << z) | (y >> (64 - z));
else
x = y;
return x;
}
unsigned long
test_RotateR_eqz (unsigned long x, unsigned long y, unsigned long z,
unsigned long c)
{
if (c)
x = (y >> z) | (y << (64 - z));
else
x = y;
return x;
}
/* { dg-final { scan-assembler-times {czero\.eqz} 28 } } */
/* { dg-final { scan-assembler-times {czero\.nez} 28 } } */