cmd/compile: don't constant fold divide by zero

It just makes the compiler crash. Oops.

Fixes #43099

Change-Id: Id996c14799c1a5d0063ecae3b8770568161c2440
Reviewed-on: https://go-review.googlesource.com/c/go/+/276652
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Author: randall77

src/cmd/compile/internal/ssa/gen/ARM.rules

@@ -760,8 +760,8 @@
 (MUL (MOVWconst [c]) (MOVWconst [d])) => (MOVWconst [c*d])
 (MULA (MOVWconst [c]) (MOVWconst [d]) a) => (ADDconst [c*d] a)
 (MULS (MOVWconst [c]) (MOVWconst [d]) a) => (SUBconst [c*d] a)
-(Select0 (CALLudiv (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [int32(uint32(c)/uint32(d))])
-(Select1 (CALLudiv (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [int32(uint32(c)%uint32(d))])
+(Select0 (CALLudiv (MOVWconst [c]) (MOVWconst [d]))) && d != 0 => (MOVWconst [int32(uint32(c)/uint32(d))])
+(Select1 (CALLudiv (MOVWconst [c]) (MOVWconst [d]))) && d != 0 => (MOVWconst [int32(uint32(c)%uint32(d))])
 (ANDconst [c] (MOVWconst [d])) => (MOVWconst [c&d])
 (ANDconst [c] (ANDconst [d] x)) => (ANDconst [c&d] x)
 (ORconst [c] (MOVWconst [d])) => (MOVWconst [c|d])

src/cmd/compile/internal/ssa/gen/ARM64.rules

@@ -1372,14 +1372,14 @@
 (MADDW a (MOVDconst [c]) (MOVDconst [d])) => (ADDconst [int64(int32(c)*int32(d))] a)
 (MSUB  a (MOVDconst [c]) (MOVDconst [d])) => (SUBconst [c*d] a)
 (MSUBW a (MOVDconst [c]) (MOVDconst [d])) => (SUBconst [int64(int32(c)*int32(d))] a)
-(DIV   (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [c/d])
-(UDIV  (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [int64(uint64(c)/uint64(d))])
-(DIVW  (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [int64(int32(c)/int32(d))])
-(UDIVW (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [int64(uint32(c)/uint32(d))])
-(MOD   (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [c%d])
-(UMOD  (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [int64(uint64(c)%uint64(d))])
-(MODW  (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [int64(int32(c)%int32(d))])
-(UMODW (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [int64(uint32(c)%uint32(d))])
+(DIV   (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [c/d])
+(UDIV  (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [int64(uint64(c)/uint64(d))])
+(DIVW  (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [int64(int32(c)/int32(d))])
+(UDIVW (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [int64(uint32(c)/uint32(d))])
+(MOD   (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [c%d])
+(UMOD  (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [int64(uint64(c)%uint64(d))])
+(MODW  (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [int64(int32(c)%int32(d))])
+(UMODW (MOVDconst [c]) (MOVDconst [d])) && d != 0 => (MOVDconst [int64(uint32(c)%uint32(d))])
 (ANDconst [c] (MOVDconst [d]))  => (MOVDconst [c&d])
 (ANDconst [c] (ANDconst [d] x)) => (ANDconst [c&d] x)
 (ANDconst [c] (MOVWUreg x)) => (ANDconst [c&(1<<32-1)] x)

src/cmd/compile/internal/ssa/gen/MIPS.rules

@@ -626,10 +626,10 @@
 (MUL (MOVWconst [c]) (MOVWconst [d])) => (MOVWconst [c*d])
 (Select1 (MULTU  (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [int32(uint32(c)*uint32(d))])
 (Select0 (MULTU  (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [int32((int64(uint32(c))*int64(uint32(d)))>>32)])
-(Select1 (DIV  (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [c/d])
-(Select1 (DIVU (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [int32(uint32(c)/uint32(d))])
-(Select0 (DIV  (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [c%d])
-(Select0 (DIVU (MOVWconst [c]) (MOVWconst [d]))) => (MOVWconst [int32(uint32(c)%uint32(d))])
+(Select1 (DIV  (MOVWconst [c]) (MOVWconst [d]))) && d != 0 => (MOVWconst [c/d])
+(Select1 (DIVU (MOVWconst [c]) (MOVWconst [d]))) && d != 0 => (MOVWconst [int32(uint32(c)/uint32(d))])
+(Select0 (DIV  (MOVWconst [c]) (MOVWconst [d]))) && d != 0 => (MOVWconst [c%d])
+(Select0 (DIVU (MOVWconst [c]) (MOVWconst [d]))) && d != 0 => (MOVWconst [int32(uint32(c)%uint32(d))])
 (ANDconst [c] (MOVWconst [d])) => (MOVWconst [c&d])
 (ANDconst [c] (ANDconst [d] x)) => (ANDconst [c&d] x)
 (ORconst [c] (MOVWconst [d])) => (MOVWconst [c|d])

src/cmd/compile/internal/ssa/gen/MIPS64.rules

@@ -617,10 +617,10 @@
 (SRLVconst [c] (MOVVconst [d]))  => (MOVVconst [int64(uint64(d)>>uint64(c))])
 (SRAVconst [c] (MOVVconst [d]))  => (MOVVconst [d>>uint64(c)])
 (Select1 (MULVU (MOVVconst [c]) (MOVVconst [d]))) => (MOVVconst [c*d])
-(Select1 (DIVV  (MOVVconst [c]) (MOVVconst [d]))) => (MOVVconst [c/d])
-(Select1 (DIVVU (MOVVconst [c]) (MOVVconst [d]))) => (MOVVconst [int64(uint64(c)/uint64(d))])
-(Select0 (DIVV  (MOVVconst [c]) (MOVVconst [d]))) => (MOVVconst [c%d])   // mod
-(Select0 (DIVVU (MOVVconst [c]) (MOVVconst [d]))) => (MOVVconst [int64(uint64(c)%uint64(d))]) // mod
+(Select1 (DIVV  (MOVVconst [c]) (MOVVconst [d]))) && d != 0 => (MOVVconst [c/d])
+(Select1 (DIVVU (MOVVconst [c]) (MOVVconst [d]))) && d != 0 => (MOVVconst [int64(uint64(c)/uint64(d))])
+(Select0 (DIVV  (MOVVconst [c]) (MOVVconst [d]))) && d != 0 => (MOVVconst [c%d])   // mod
+(Select0 (DIVVU (MOVVconst [c]) (MOVVconst [d]))) && d != 0 => (MOVVconst [int64(uint64(c)%uint64(d))]) // mod
 (ANDconst [c] (MOVVconst [d])) => (MOVVconst [c&d])
 (ANDconst [c] (ANDconst [d] x)) => (ANDconst [c&d] x)
 (ORconst [c] (MOVVconst [d])) => (MOVVconst [c|d])